Gets the currently active multiple-document interface (MDI) child window.
(in System.Windows.Forms.dll)
Visual Basic (Declaration)
<BrowsableAttribute(False)> _
Public ReadOnly Property ActiveMdiChild As Form
Dim instance As Form
Dim value As Form
value = instance.ActiveMdiChild
[BrowsableAttribute(false)]
public Form ActiveMdiChild { get; }
[BrowsableAttribute(false)]
public:
property Form^ ActiveMdiChild {
Form^ get ();
}
public function get ActiveMdiChild () : Form
Property Value
Type:
System.Windows.Forms..::.FormReturns a Form that represents the currently active MDI child window, or nullNothingnullptra null reference (Nothing in Visual Basic) if there are currently no child windows present.
You can use this method to determine whether there are any MDI child forms open in your MDI application. You can also use this method to perform operations on an MDI child window from its MDI parent form or from another form that is displayed in your application.
If the currently active form is not an MDI child form, you can use the ActiveForm property to obtain a reference to it.
The following code example obtains a reference to the active MDI child form and loops through all TextBox controls on the form, resetting their Text properties. This example requires that an MDI parent form has been created and that this method call is being made from the MDI parent form.
Public Sub ClearAllChildFormText()
' Obtain a reference to the currently active MDI child form.
Dim tempChild As Form = Me.ActiveMdiChild
' Loop through all controls on the child form.
Dim i As Integer
For i = 0 To tempChild.Controls.Count - 1
' Determine if the current control on the child form is a TextBox.
If TypeOf tempChild.Controls(i) Is TextBox Then
' Clear the contents of the control since it is a TextBox.
tempChild.Controls(i).Text = ""
End If
Next i
End Sub 'ClearAllChildFormText
public void ClearAllChildFormText()
{
// Obtain a reference to the currently active MDI child form.
Form tempChild = this.ActiveMdiChild;
// Loop through all controls on the child form.
for (int i = 0; i < tempChild.Controls.Count; i++)
{
// Determine if the current control on the child form is a TextBox.
if (tempChild.Controls[i] is TextBox)
{
// Clear the contents of the control since it is a TextBox.
tempChild.Controls[i].Text = "";
}
}
}
public:
void ClearAllChildFormText()
{
// Obtain a reference to the currently active MDI child form.
Form^ tempChild = this->ActiveMdiChild;
// Loop through all controls on the child form.
for ( int i = 0; i < tempChild->Controls->Count; i++ )
{
// Determine if the current control on the child form is a TextBox.
if ( dynamic_cast<TextBox^>(tempChild->Controls[ i ]) )
{
// Clear the contents of the control since it is a TextBox.
tempChild->Controls[ i ]->Text = "";
}
}
}
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
.NET Framework
Supported in: 3.5, 3.0, 2.0, 1.1, 1.0
Reference
Other Resources