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• How do I put my form in "design mode"?

  See the DesignModeDialog sample. This sample is a component, much like the common dialogs, that has a ShowDialog method. When invoked, ShowDialog takes a snapshot of the parent form, clones all the controls and creates a new designer form with the controls...

• How can I host a designer in my app?

  The new DesignSurface class drastically simplifies the code necessary to host a designer in your own application. The following lines of code show the most simple designer that can be created. Note: to run this code, a reference to System.Design.dll will...

• How do I change the icon for a custom control in the Toolbox?

  You can do this in different ways explained below. In all the cases the bitmap or icon should follow these rules: The bitmap or icon dimension should be 16x16 with 16 colors. The bottom-left pixel color will be assumed to be the transparent color. Technique...

• How do I provide dynamic default values for components or controls?

  Provide ShouldSerialize and Reset Methods along with your property. Example: private bool ShouldSerializeFont() { return this.bFontSet; } private void ResetFont() { this.localFont = null; } Contributed from George Shepherd's Windows Forms FAQ

• How to make properties in your custom data type appear in a particular order in the property browser?

  For example, if you have a custom type: public class CustomSize { public int Width { get { /*...*/ } set { /*...*/ } } public int Height { get { /*...*/ } set { /*...*/ } } } And you want to the Width and Height properties to appear in that order, then...

• How do I make properties of custom data types browsable in the Property browser?

  If you have a custom data type like this: public class CustomSize { public int Width { get { /*...*/ } set { /*...*/ } } public int Height { get { /*...*/ } set { /*...*/ } } } Then write this: public class CustomSizeConverter : ExpandableObjectConverter...

• How can I tell my form is being used in design time and not runtime?

  Check the Form.DesignMode property. But note that when in Visual Inheritance mode (designing a derived form), your control's DesignMode property will be true when the base form's constructor gets executed in the design-time. To workaround this...

• What is the function of TypeConverters?

  Type converters let you convert one type to another type. Each type that you declare can optionally have a TypeConverter associated with it using the TypeConverterAttribute. If you do not specify one the class will inherit a TypeConverter from its base...

• How do I make a property browsable in the editor, but not browsable in the designer?

  Provide the followoing attributes to your Property: [ Browsable( false ), EditorBrowsable( EditorBrowsableState.Always ) ] public bool CustomProperty{ get{} set{} } Contributed from George Shepherd's Windows Forms FAQ

• How do I hide a base class property in my derived control from the user at design-time?

  Set the Browsable attribute on the new property that hides the existing one. Here is a code snippet that hides the WordWrap property in the derived TextBox. [C#] public class CustomTextBox : TextBox { [ Browsable( false ) ] public new bool WordWrap {...

• How do I prevent certain controls from being displayed in the Property browser at design-time?

  Use the DesignTimeVisible attribute set to false. [ DesignTimeVisible( false ) ] You can still provide a TypeConverter to make it participate in designer Serialization. Contributed from George Shepherd's Windows Forms FAQ

• How do I prevent a component from being displayed in the Toolbox in Visual Studio?

  Use the ToolboxItem attribute set to false on your component or control class. This will prevent it from appearing in the Toolbox. [ ToolboxItem( false ) ] public class MyComponent : Component{..} Contributed from George Shepherd's Windows Forms FAQ

• Why does calling Focus() on a control not set focus on it?

  When you call the Focus method on a control, the control must be visible; otherwise focus will not be set. For example, if you call Focus on a control in Form_Load then focus will not be set. Instead consider setting the control's TabIndex property...

• How do I find out which control has focus?

  The .NET Framework Class Library does not provide a method to determine which control has keyboard focus, but you can invoke a Win32 API function to do this. Here's a custom form class that adds a GetFocusControl method to retrieve the .NET control...

• How do I process Windows messages in a control?

  Override the control's WndProc method. This sample shows a custom control that is a ComboBox that discards the WM_KEYUP message. [C#] using System.Windows.Forms; public class ComboBoxWithNoKeyUp : ComboBox { private const int WM_KEYUP = 0x101; protected...

• How do I get started creating custom controls?

  See Developing a Simple Windows Forms Control from .NET Framework Developer's Guide for a walk-through about creating Windows Forms custom controls. Tom Krueger, Microsoft