Control.Dock Property

Gets or sets which control borders are docked to its parent control and determines how a control is resized with its parent.

Namespace: System.Windows.Forms
Assembly: System.Windows.Forms (in

<LocalizableAttribute(True)> _
Public Overridable Property Dock As DockStyle
Dim instance As Control
Dim value As DockStyle

value = instance.Dock

instance.Dock = value
/** @property */
public DockStyle get_Dock ()

/** @property */
public void set_Dock (DockStyle value)

public function get Dock () : DockStyle

public function set Dock (value : DockStyle)

Not applicable.

Property Value

One of the DockStyle values. The default is None.

Exception typeCondition


The value assigned is not one of the DockStyle values.

Use the Dock property to define how a control is automatically resized as its parent control is resized. For example, setting Dock to DockStyle.Left causes the control to align itself with the left edges of its parent control and to resize as the parent control is resized. Controls are docked in their Z-order, which is the visual layering of controls on a form along the form's Z-axis (depth).

A control can be docked to one edge of its parent container or can be docked to all edges and fill the parent container.

Setting the Margin property on a docked control has no effect on the distance of the control from the the edges of its container.


The Anchor and Dock properties are mutually exclusive. Only one can be set at a time, and the last one set takes precedence.

Notes to Inheritors: When overriding the Dock property in a derived class, use the base class's Dock property to extend the base implementation. Otherwise, you must provide all the implementation. You are not required to override both the get and set methods of the Dock property; you can override only one if needed.

The following code example creates a GroupBox and sets some of its common properties. The example creates a TextBox and sets its Location within the group box. Next, it sets the Text property of the group box, and docks the group box to the top of the form. Lastly, it disables the group box by setting the Enabled property to false, which causes all controls contained within the group box to be disabled.

' Add a GroupBox to a form and set some of its common properties.
Private Sub AddMyGroupBox()
   ' Create a GroupBox and add a TextBox to it.
   Dim groupBox1 As New GroupBox()
   Dim textBox1 As New TextBox()
   textBox1.Location = New Point(15, 15)
   ' Set the Text and Dock properties of the GroupBox.
   groupBox1.Text = "MyGroupBox"
   groupBox1.Dock = DockStyle.Top
   ' Disable the GroupBox (which disables all its child controls)
   groupBox1.Enabled = False
   ' Add the Groupbox to the form.
End Sub

// Add a GroupBox to a form and set some of its common properties.
private void AddMyGroupBox()
    // Create a GroupBox and add a TextBox to it.
    GroupBox groupBox1 = new GroupBox();
    TextBox textBox1 = new TextBox();
    textBox1.set_Location(new Point(15, 15));
    // Set the Text and Dock properties of the GroupBox.
    // Disable the GroupBox (which disables all its child controls)
    // Add the Groupbox to the form.
} //AddMyGroupBox

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0