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• Using Controls (87)

• How do I add custom ColumnStyles to the designer so I can use them in a DataGrid at design time?

  To use custom ColumnStyles in the designer, you need to do three things. 1) Derive a CustomColumnStyle to implement the functionality you want. 2) Derive a DataGridTableStyle class and add a new GridColumnStyles property that uses this derived CollectionEditor...

• Why did I lose the settings on a DataGrid set during design-time?

  This is possible if you assign a custom DataGridTableStyle to the DataGrid. The properties in the DataGridTableStyle will then replace certain properties in the DataGrid. Take a look at DataGrid class reference for a list of these properties. Contributed...

• How do I perform custom handling of a double-click in a DataGrid's column header cell?

  You can handle the DataGrid's DoubleClick event, and use the HitTest method to test if the double-click was on a column header. using System; using System.Drawing; using System.Windows.Forms; private DataGrid dataGrid1; // ... dataGrid1.DoubleClick...

• How do I translate a point to a cell in a DataGrid?

  If the point is in screen coordinates, then convert it to client coordinates of the DataGrid and use HitTest to find the row and column. using System.Drawing; using System.Windows.Forms; private DataGridCell CellFromPoint( DataGrid dataGrid, Point pointInScreenCoords...

• How do I prevent a DataGrid from highlighting cells when the user clicks in it?

  Set the DataGrid's Enabled property to false. Contributed from George Shepherd's Windows Forms FAQ This FAQ item is current to the .NET Framework 1.1 release. Please report status updates here .

• How do I determine which rows are selected in a DataGrid?

  You could derive a control from DataGrid and add a SelectedItems property, along the lines of ListView.SelectedItems, like this: using System.Collections; using System.Data; using System.Windows.Forms; public class DataGridSelectedItems : DataGrid { public...

• How do I select an entire row when the user clicks in a DataGrid?

  Handle the DataGrid's MouseUp event, and within the hander call the DataGrid.Select method. using System.Drawing; using System.Windows.Forms; private DataGrid dataGrid1; // ... dataGrid1.MouseUp += new MouseEventHandler( dataGrid1_MouseUp ); // ....

• How do I programmatically select a row in DataGrid?

  Use the DataGrid.Select method. using System.Windows.Forms; DataGrid dataGrid1; // ... dataGrid1.Select( 1 ); // select row 1 Contributed from George Shepherd's Windows Forms FAQ

• How do I retrieve the current row from a DataTable to which a DataGrid is bound after the grid has been sorted?

  In an unsorted DataGrid bound to a DataTable, you can get a reference to a row in the DataTable through the DataGrid.CurrentRowIndex. DataTable dataTable = (DataTable) dataGrid1.DataSource; DataRow dataRow = dataTable.Rows[ dataGrid1.CurrentRowIndex ...

• How do I allow the user to select cell ranges in a DataGrid using the mouse?

  The Windows Forms DataGrid does not support the selection of a range of cells other than a group of rows. To select a row, you can click on its row header. But if you want to select a rectangular group of cells, you cannot. To add this support, you can...

• How do I iterate through all the rows and columns in a DataGrid?

  You use the row index and column index as indexers on the DataGrid object. private void IterateOverDataTable() { CurrencyManager cm = (CurrencyManager) BindingContext[ dataGrid1.DataSource ]; int rowCount = cm.Count; // assumes data source is a DataTable...

• How can I enable column selections in a DataGrid?

  Here is a sample ( C# , VB ) that has column selections implemented. It derives a DataGrid, adds a columns selection array list, and maintains this list in an override of OnMouseDown. Then to handle actually drawing the selected columns, it uses a derived...

• How do I determine the row and column of the current cell in a DataGrid?

  You can use the CurrentCell property of the DataGrid. private void button1_Click(object sender, System.EventArgs e) { int colNum = dataGrid1.CurrentCell.ColumnNumber; int rowNum = dataGrid1.CurrentCell.RowNumber; object cellValue = dataGrid1[rowNum, colNum...

• How do I determine the row or column of a DataGrid that has been clicked on?

  You can use the DataGrid's HitTest method, passing it a point in the grid's client coordinate system, and returning a HitTestInfo object that holds all the row and column information that you want. X & Y are in the grid' coordinates. If...

• How do I get the selected text in the active cell of a DataGrid?

  You need to get the DataGridTextBoxColumn.TextBox member, and retrieve the SelectedText from it for the active cell. The sample shows how you can do this as part of handling this TextBox's rightClick. This code assumes you have specifically added...

• How do I restrict the keystrokes that are accepted in a DataGrid column?

  The sample project DataGridRestrictedInput illustrates how to restrict a column to only accept digits. The technique is general and you can apply it to other kinds of restricted input. Here's the basic idea. You create a custom column style that derives...

• How do I get a DataGrid's column header text in a MouseUp event?

  using System; using System.Data; using System.Drawing; using System.Windows.Forms; // ... private void dataGrid1_MouseUp(object sender, MouseEventArgs e) { Point point = new Point( e.X, e.Y ); DataGrid.HitTestInfo hti = dataGrid1.HitTest( point ); if...

• How do I prevent sorting a single column in a DataGrid?

  You can do this by deriving the DataGrid and overriding the OnMouseDown method. In the override, do a HitText and if the hit is on a column header that you do not want to sort, do not call the base class's method. Here is a code that sorts all columns...

• How do I prevent a DataGrid from allowing new rows to be added, and so suppress display of the append row (i.e., the row at the end with an asterisk)?

  The DataGrid class does not have a property that controls whether a new row can be added. But the DataView class does have such an AllowNew property (among others such as AllowEdit and AllowDelete). Here is code that will turn off the append row by getting...

• How do I detect when a DataGrid cell starts being edited, as opposed to when it becomes the current cell?

  You can use the CurrentCellChanged event to detect when the currentcell changes position. But this event will not allow you to catch the start of a cell being edited. One way you can do this is to catch the TextChanged event in the embedded TextBox within...

• Why does a column with custom style in a DataGrid not receive focus when Tab is pressed to enter the column?

  This behavior can be seen when you embedded a control like a TextBox or ComboBox in your derived GridColumnStyle. If you press the Tab key slowly, you may see the cell get focus on the KeyDown and the cell lose focus on the KeyUp. One way to avoid this...

• How do I prevent the cells in a DataGrid from being edited without deriving GridColumnStyle?

  One solution is to remove all the editing controls from the DataGrid.Controls collection. Without these controls the grid contents cannot be edited. There is a technical problem that requires a little care. You do not want to delete all the controls in...

• How do I make a DataGrid column automatically adjust keyboard input? For example, typing 12312002 should be automatically adjusted as the date 12/31/2002.

  One possible solution is that as you move off the cell, you get the typed value, and modify it before it is passed onto the DataGrid for its standard processing. One problem is that there are several ways to leave the cell, and you would want to handle...

• How do I format columns in a DataGrid without adding DataGridColumnStyles?

  To format column output, you do not have to explicitly add DataGridColumns for each column provided you do add a DataGridTableStyle to your DataGrid prior to setting the DataSource property. When you set the DataSource property with a DataGrid that has...

• How do I use events to restrict key input in DataGrid cells?

  If you make sure your DataGrid is using a DataGridTableStyle, then you can access the TextBox through the GridColumnStyles collection and hook the event there. Here is some code. [C#] //in formload this.dataGrid2.DataSource = this.dataSet11.Customers;...

• How do I get a CheckBox column in a DataGrid to respond to the first click?

  When you first click into a CheckBox column, the checked state of the cell does not change. One way you can make the checked state change on the first click is to handle the grid's MouseUp event, and change the check value there. [C#] private int...

• How do I catch when the user clicks off a DataGrid, for example to close the form?

  You can catch clicking off a DataGrid in the DataGrid.Validated event. But this event is also hit when you use the Tab key to move around the grid. So if you want to catch it exclusively for clicking off the grid, you have to ignore the event due to the...

• If the user selects a row in a DataGrid, then scrolls it out of view with the mouse wheel, the user cannot get the selected row back into view. How do I work around this limitation?

  When you select a row in the DataGrid and scroll it out of view using the mouse wheel, you cannot get it back into view. Here is a workaround. dataGrid1.MouseWheel += new MouseEventHandler( dataGrid1_MouseWheel ); // ... private void dataGrid1_MouseWheel...

• How do I make the Enter key behave like the Tab key in a DataGrid, moving to the next cell?

  You can override ProcessCmdKey, catch the Enter key, and swap it for a Tab key by sending a Tab, and not processing the Enter key. public class CustomDataGrid : DataGrid { protected override bool ProcessCmdKey( ref Message msg, Keys keyData ) { if ( msg...

• How do I put up a confirmation dialog when the user tries to delete a row in the DataGrid by clicking on the row header and pressing the Delete key?

  You can handle this by subclassing your grid and overriding either PreProcessMessage or ProcessDialogKey. The code below assumes your datasource is a dataview. If it is not, you could just remove that check [C#] public class CustomDataGrid : DataGrid...

• How do I programmatically select a row in a DataGrid and have no cell active, just like when the user clicks on a row header?

  This code adds a method to a derived grid that simulates a mouseclick on the rowheader of the row passed into the method. using System.Runtime.InteropServices; public class CustomDataGrid : DataGrid { public const int WM_LBUTTONDOWN = 513; // 0x0201 public...

• How do I catch the values changing in a DataGridBoolColumn in a DataGrid?

  There is no event fired when the Boolean value changes. In the attached sample ( C# , VB ), a BoolValueChanged event has been added to a columnstyle derived from DataGridBoolColumn. Catching the changes requires some effort. The strategy is to save the...

• How do I prevent the user from resizing columns in a DataGrid?

  You can do this by subclassing your grid and overriding OnMouseMove, and not calling the baseclass if the point is on the columnsizing border. [C#] public class CustomDataGrid : DataGrid { // prevent display of resizing cursor protected override void...

• How do I catch a double-click event in a DataGrid?

  The problem is that the first click of a double click may be caught by the datagrid (and used to activate the cell) while the second click goes to the TextBox for the columnstyle object. This means the TextBox thinks this is a singleclick, and does not...

• How to I get tabbing to work properly in a DataGrid that has hidden columns (i.e., column width is zero)?

  As you tabbed to the right side of your grid, you tabbed through these zero width column and that is causing the tab key to appear not to work properly. One solution is to handle the grid's CurrentCellChanged event, and if you are on a border cell...

• How do I make a DataGrid never have an active edit cell and always select whole rows as in a browser-style grid?

  For a single row select DataGrid, you can get both these behaviors by using a custom column style and overriding its Edit method. In your override, handle unselecting and selecting the current row, and DO NOT call the base class. Not calling the base...

• How do I make a DataGrid have no current cell?

  There appears to be no method to turn off a currentcell. When a cell is being edited, it is the TextBox embedded in the columnstyle that has the focus, and is displaying the highlighted text. You will notice in this situation, if you click the grid's...

• How do I get tooltips to vary by cell in a DataGrid?

  One way to do this is to use a ToolTip control and reset the control text as the mouse moves across cells. Below is a derived DataGrid class that implements this idea. The main points are: Have members that track the current hitRow and hitCol where the...

• How do I prevent moving to the next cell in a DataGrid when the user is actively editing the cell and presses Enter?

  Override the method ProcessKeyPreview in the DataGrid. protected override bool ProcessKeyPreview( ref Message m ) { Keys keyCode = (Keys) (int) m.WParam & Keys.KeyCode; if ( ( m.Msg == WM_KEYDOWN || m.Msg == WM_KEYUP ) && keyCode == Keys.Enter...

• How do I determine whether a CheckBox in a DataGrid is checked?

  If the column is a boolean column, you can just cast the object returned by the indexer to a bool. bool checked = (bool)dataGridTopics[ row, column ]; Contributed from George Shepherd's Windows Forms FAQ

• How do I tell if a DataGrid's current row has changed and whether the user is on the AddNew row?

  The DataGrid's CurrentCellChanged event is hit even if you just change cells in the current row. If you want an event that is only hit when you change rows, then you have to look at the binding manager. This object has both a CurrentChanged event...

• How do I subclass the TextBox of a column in a DataGrid so that I can implement custom behavior?

  I want to do custom handling of special keys such as the Tab key or F2 in the TextBox of a column in the DataGrid. How do I subclass this TextBox to get at it virtual members? The TextBox property of the DataGridTextBoxColumn is ReadOnly, so you just...

• How do I move rows in a DataGrid by dragging the row header cell?

  One way to implement this is to derive a DataGrid and override the virtual OnMouseDown, OnMouseMove and OnMouseUp methods. In your overrides, if the mousedown is on a row header, track the initial mousedown row, and as it moves, draw a line to indicate...

• How do I perform validation on a per-cell basis in a DataGrid?

  There are problems trying to implement cell by cell validation using the grid's Validating event architecture. The problem is that the grid is not the object handling the data. Instead, a TextBox or some other control is the control managing the changing...

• How do I prevent a particular cell in a DataGrid from being editable?

  You can do this by deriving a custom column style and overriding its virtual Edit member. Below is an override that will prevent the cell in row 1 of the column from getting the edit focus. You can paste this code in the DataGridDigitsTextBoxColumn sample...

• How do I make a column in a DataGrid automatically increment as new rows are added?

  DataTable myTable = new DataTable("Customers"); ... DataColumn cCustID = new DataColumn("CustID", typeof(int)); cCustID.AutoIncrement = true; cCustID.AutoIncrementSeed = 1; cCustID.AutoIncrementStep = 1; myTable.Columns.Add(cCustID...

• How do I get notification of the changing of a value in a column of ComboBoxes in a DataGrid?

  This solution is based off the combobox for datagrid columns found in this FAQ . That solution replaces the standard textbox with a combobox. To get notifications of the changes, a delegate is passed into the constructor for the custom column style. This...

• How do I add an unbound column to a DataGrid that is bound to a data source?

  The idea is to create the 'bound' table in your dataset, and then add an extra 'unbound' column. The steps are to derive a custom columnstyle that overrides Paint where you calculate and draw the unbound value. You can also override Edit...

• How do I display master-details-subdetails in three separate DataGrids?

  Here is a sample (both VB and C#) that illustrates how to have a parent table which has a related child table, which also has a related grandchild table. Below are some code snippets. The trick is to always make the main parent table be the DataSource...

• How do I use data from two DataTables in a single DataGrid to display join of the two tables?

  Take a look at the Microsoft KB article: HOW TO: Extend the Windows Form DataGridTextBoxColumn to Display Data From Other Tables by Using Visual C# .NET (Article ID: 319076) or HOW TO: Extend the Windows Form DataGridTextBoxColumn to Display Data From...

• How do I bind two DataGrids in a master-detail relationship?

  Please download this sample before reading the rest of this FAQ. Looking through the sample will help follow the description. simpledata2.zip What this boils down to is this: 1) Load both Master and Details queries in a dataset. // I am using the SQL...

• How do I bind a DataGrid to an ArrayList of objects?

  Here is a technique for binding an ArrayList of objects where the objects contain public properties that should appear as columns in the DataGrid. To bind an ArrayList of these objects to a DataGrid, add a custom DataGridTableStyle that has a MappingName...

• How do I bind a DataGrid to a data source without using any wizards?

  Here is a really simple data binding sample. Just drag and drop a DataGrid onto a default Windows Forms application. Follow the steps below to bind this grid to the NorthWind db in SQL server. Complete Sample: simpledata.zip // Create a connection SqlConnection...

• How do I force the vertical scrollbar in a DataGrid to always be visible?

  Derive a DataGrid. In your derived grid, add a handler for the VertScrollBar.VisibleChanged event. In your handler, if the scrollbar is not visible, size it and position it, and then show it. The code below assumes no horizontal scrollbar is necessary...

• How do I tell whether a DataGrid's scrollbar is visible?

  If you are using a derived DataGrid, then you can check the Visible property on the protected VertScrollBar property of DataGrid. So, you could check Me.VertScrollBar.Visible from within your derived DataGrid. To check it without access to the protected...

• How do I programmatically scroll a DataGrid to a particular row?

  The DataGrid has a protected GridVScrolled member that can be used to scroll the grid. To use it, you can derive from DataGrid and add a ScrollToRow method. Here is a code snippet. Public Class MyDataGrid Inherits DataGrid Sub ScrollToRow(ByVal row As...

• How do I put a CheckBox in a column of a DataGrid?

  You create a custom DataTableStyle that contains column styles for each column you want to display. You add the column styles in the order you want them to appear. Here are the steps to add an string column, an int column and a bool check column to a...

• How do I create a column of icons in my DataGrid?

  You need to derive a custom column style, override its Paint method and draw the image. In the attached samples, ( VB and C# ), there are two custom column styles. One style is a stand-alone unbound column that just displays an image. The second custom...

• How do I format a date column in a DataGrid?

  If you have added a table style to your DataGrid (so individual column styles have been generated), then you can use code such as this to set the Format property of the particular column style. [C#] // add format column 3 columnstyle where column 3 holds...

• How do I use the DataColumn.Expression property to add a computed or combined column to a DataGrid?

  The idea is to load your datatable in a normal fashion. Once the datatable is loaded, you can add an additional column that is computed from the other columns in your datatable. In the sample ( CS , VB ), we load the CustomerID, CompanyName, ContactName...

• How do I create a column of bitmaps in a DataGrid?

  You can derive a custom columnstyle and override its Paint method to draw the image. Here are both C# and VB.Net samples . The Paint override offers three ways to draw the bimap in the cell; size it to fit the cell bounds, size it proportionally to fit...

• How do I create a ComboBox column in a DataGrid?

  There are several ways to go about this task. The simplest way involves adding a single combobox to the DataGrid.Controls, and then selectively displaying it as needed when a combobox cell becomes the currentcell. All the work is done in a few event handlers...

• How do I display a column of Buttons or ComboBox buttons in a DataGrid?

  This sample ( download C# , download VB ) derives two custom columnstyles that display buttons. One displays a pushbutton with the cell text used as the button label. The second columnstyle displays text plus a dropdown button similar to a combobox button...

• How do I make the last column of a DataGrid fill the remaining client area?

  If you have added a TableStyle for your grid, then the code below should set the right column width to be the empty space from a button click. If you need to dynamically do this in response to the user sizing other columns, then there may be more work...

• How do I automatically size a column in a DataGrid?

  One way to do this is to use MeasureString to compute the size of the text in each cell, and then take the maximum value. Below is a code snippet that does this. It assumes your datagrid is bound to a datatable. You can download a full working sample...

• How do I add and remove columns in my DataGrid without modifying the DataTable data source?

  You can control the columns displayed in the DataGrid through the DataGrid.TableStyle[0].GridColumnStyles collection. To do so, create a DataGridTableStyle and set its MappingName property to point to the name of your DataTable which is the DataSource...

• How do I programmatically set the height of a row in a DataGrid?

  DataGrid does not expose row height through a public member. However it is possible to set row heights using reflection to access the DataGrid internal row properties, based on a suggestion from Matthew Benedict. Here is a sample project (C# and VB) showing...

• How do I automatically size columns in a DataGrid so they fill the grid's client area?

  If you add a DataGridTableStyle to your DataGrid, then you can use the ColWidth property of the GridColumnStyles to set the width of each column. To dynamically set these widths as the grid is resized, you can handle the SizeChanged event of the DataGrid...

• How do I set the width of a column in a DataGrid?

  To set a column width, your DataGrid must be using a non-null DataGridTableStyle. Once this is in place, you can set the column width by first getting the tablestyle and then using that object to obtain a column style with which you can set the width...

• How do I hide a column in a DataGrid?

  There are several ways to hide a column: 1) You can use your DataSet's ColumnMapping property to hide a column. // Creating connection and command sting string conStr = @"Provider=Microsoft.JET.OLEDB.4.0;data source=C:\northwind.mdb"; string...

• How do I automatically size the row heights in a DataGrid?

  Here is a solution suggested by Matthew Benedict. It uses reflection to access the protected DataGridRows collection so he can set the row height. public void AutoSizeGrid() { // DataGrid should be bound to a DataTable for this part to // work. int numRows...

• How do I change the width of the row or column headers in a DataGrid or hide them completely?

  You can get at the width and visibility of the header row/column through a DataGridTableStyle. DataGridTableStyle has properties such as RowHeadersVisible and RowHeadersWidth. DataGridTableStyle also controls things like selections colors and GridLine...

• How do I display text in the row header column of a DataGrid?

  There is no text property exposed for a rowheader cell. But you can handle the Paint event and draw header text yourself. You can download sample projects ( C# , VB ) that illustrate one technique for doing so. The sample loads the DataGrid in the form's...

• How do I prevent the plus-minus icon that appears next to the row header when I have a DataGrid bound to a data source that has a relation defined?

  Set the DataGrid.AllowNavigation property to false. Contributed from George Shepherd's Windows Forms FAQ

• How do I display rows in a DataGrid in a free-form layout using TextBoxes on a Panel?

  Here is a VB and C# sample showing how you might do this. The idea is to add TextBoxes and Lables to a Panel with whatever layout you want to use. Then use DataBindings.Add calls to bind the TextBoxes to columns in your grid's datasource. Then, since...

• How do I make the DataGrid column be blank and not display "(null)" as the default value?

  When the user adds a new row in a DataGrid, the columns display "(null)". To prevent this behavior and make all the columns be empty, you can set the DefaultValue property of the DataColumn to be String.Empty. Contributed from George Shepherd's...

• How do I set default values for new rows in a DataGrid?

  You use the DataColumn.DefaultValue property to provide default values for new rows. You access this property through the DataTable associated with the DataGrid, [C#] dataGrid1.DataSource = dataSet.Tables[ "orders" ]; // default value for column...

• How do I control the cursor over a DataGrid?

  One way you can do this is to derive a class from DataGrid and override its WndProc method to handle the WM_SETCURSOR method. In your override, you can do hit testing to decide when you want to set the cursor, or when you want to call the base class and...

• How do I change the font in a DataGrid cell or row?

  One way to do this is to use a derived columnstyle, override the Paint method and do the text drawing yourself, using whatever font or colors you like. If you add an event to your derived column style that is fired immediately before the text is drawn...

• How do I specially color only the current cell of a read-only DataGrid?

  You can use the first technique listed in this FAQ: How do I color an individual cell depending upon its value or some external method? The idea is to derive a custom columnstyle. override its Paint method to specially color the background of the currentcell...

• How do I display negative values in a DataGrid with a CR suffix, instead of a minus sign prefix?

  Take a look at this Microsoft KB article, HOW TO: Extend the Windows Form DataGridTextBoxColumn Control to Custom-Format Data (Q318581) . It subclasses a DataGridColumnStyle and overrides both GetColumnValueAtRow and Commit to implement this behavior...

• How do I get rid of the error icon that appears when there is an error editing a DataGrid?

  DataTable dt = (DataTable) dataGrid1.DataSource; foreach ( DataRow row in dt.GetErrors() ) { row.RowError = string.Empty; foreach ( DataColumn col in dt.Columns ) row.SetColumnError( col, string.Empty ); } Adam Chester

• How do I find the top-left visible cell in a DataGrid?

  In a Windows Forms DataGrid, there is no property exposed that gives you this information. But here is little trick that will allow you to get the top-left visible cell. 1) Add a private member Point pointInCell00 to the form containing the DataGrid....

• How do I determine the number of rows in a DataGrid?

  One way you can do this is through the BindingManager.Count property. [C#] int numRows = dataGrid1.BindingContext[ dataGrid1.DataSource, dataGrid1.DataMember ].Count; Contributed from George Shepherd's Windows Forms FAQ

• How do I color a cell in a DataGrid depending upon its value or some external method?

  We give three different methods for doing this. The first one overrides Paint in a derived columnstyle and sets the backcolor there. The second uses a delegate to set the color in the Paint override. The third method adds an event to the derived column...

• How do I hide a DataGrid's gridlines of or set them to a particular color?

  If your datagrid does not have a custom TableStyle associated with it, then there are two DataGrid properties that control the color and visibility of the gridlines. DataGrid..GridLineColor DataGrid.GridLineStyle If you have a custom TableStyle. you need...

• How do I rearrange the columns in a DataGrid?

  The columns appear in the order that their column styles were added to the tablestyle being used by the grid. If you want to change this order, you would need to create a new table style, and add the columnstyles in the order you want things to appear...