Gets or sets the state of the CheckBox.
Assembly: System.Windows.Forms (in System.Windows.Forms.dll)
If the ThreeState property is set to false, the property value can only be set to CheckState.Indeterminate in code and not by user interaction.
The following code example displays the values of three properties in a label. The ThreeState property alternates between true and false with alternating clicks of the control and the CheckAlign alternates between the MiddleRight and MiddleLeft values of System.Drawing.ContentAlignment. This example shows how the property values change as the ThreeState property changes and the control is checked. This example requires that a CheckBox, Label and Button have all been instantiated on a form and that the label is large enough to display three lines of text, as well as a reference to the System.Drawing namespace. This code should be called in the Click event handler of the control.
Private Sub AdjustMyCheckBoxProperties() ' Change the ThreeState and CheckAlign properties on every other click. If Not checkBox1.ThreeState Then checkBox1.ThreeState = True checkBox1.CheckAlign = ContentAlignment.MiddleRight Else checkBox1.ThreeState = False checkBox1.CheckAlign = ContentAlignment.MiddleLeft End If ' Concatenate the property values together on three lines. label1.Text = "ThreeState: " & checkBox1.ThreeState.ToString() & ControlChars.Cr & _ "Checked: " & checkBox1.Checked.ToString() & ControlChars.Cr & _ "CheckState: " & checkBox1.CheckState.ToString() End Sub
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.