Change a Property of a Control on a Form

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Reference Properties of a Control on a Form

The IDesignerHost object is used to reference properties of a form, as well as the properties of any of the components on the form.

The following code snippet demonstrates how to reference a property of the form. In this code, the Size property is referenced because it is a little different from a simple String property. To reference the Size property or the Location property, you must use the System.Drawing.Size object. The following code snippet assumes that the active window contains a WinForms Designer. The code is commented well enough to describe what is taking place in the code. For more details on manipulating controls, see Chapter 6 and the code for that chapter. Note that you must always have an IDesignerHost object to reference anything on a form, including the form's properties or component properties.

    ' Get a forms designer host object    Dim fdHost As IDesignerHost    If applicationObject.ActiveWindow.       Caption.EndsWith("[Design]")Then       Dim sName As String, sText As String       fdHost = CType(applicationObject.ActiveWindow.Object, _          IDesignerHost)       " Get and set the value of the size proeprty,       " showing values       " before and after.       Dim pd As PropertyDescriptor       pd = pdc("Size")       MsgBox("Default Button size = " + _          pd.GetValue(btn1).ToString())       Catch e As System.Exception          MsgBox(e.Message)       End Try End If

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