I encountered this nasty .NET 1.1 SP1 bug in the Windows.Forms groupbox control yesterday, and unfortunately the workaround is not that straightforward to implement in reality.
My own less-than-perfect workaround is instead to disable FlatStyle on nested groupboxes. Here's the method I use to apply the styles:
#region SetObjectPropertyValue
/// <summary>
/// Attempts to set the value of a property of an object.
/// Returns true if successful, false if not.
/// </summary>
/// <param name="objectInstance">The instance of the object</param>
/// <param name="propertyName">The name of the property</param>
/// <param name="propertyValue">The desired value of the property</param>
/// <returns>True if successful, false if not.</returns>
public static bool SetObjectPropertyValue(object objectInstance, string propertyName, object propertyValue)
{
bool isSet = false;
try
{
//use reflection to attempt to set the FlatStyle of controls
Type controlType = objectInstance.GetType();
//attempt to get the Control's specified property
PropertyInfo prop = controlType.GetProperty(propertyName);
//if it exists and is settable, set it
if (prop != null && prop.CanWrite)
{
prop.SetValue(objectInstance, propertyValue, null);
isSet = true;
}
}
catch {}
return isSet;
}
#endregion (SetObjectPropertyValue)
#region SetFlatStyleSystem
/// <summary>
/// Method used recursively to set the FlatStyle property to system
/// for all descendants of a control. Called from the form's constructor.
/// </summary>
/// <remarks>
/// Originally copied from Chris Sells' Windows Forms Programming in C#,
/// then embellished by Oskar Austegard (added Reflection).
/// Requires that the main form's Main() method includes the line
/// <code>Application.EnableVisualStyles();</code>
/// prior to showing any UI.
/// </remarks>
/// <param name="parent">Control to start with</param>
public static void SetFlatStyleSystem(Control parent)
{
Application.DoEvents();
//loop through any & all child controls
foreach(Control control in parent.Controls)
{
//don't do this for labels (changes their vertical alignment)
//and for groupboxes contained within other groupboxes (which due to a bug render with a large font)
if (!(control is Label || (control is GroupBox && control.Parent is GroupBox)))
{
SetObjectPropertyValue(control, "FlatStyle", FlatStyle.System);
}
//Set contained controls' FlatStyle as well
SetFlatStyleSystem(control);
}
}
#endregion
