Gets or sets the starting point of text selected in the text box.
Assembly: System.Windows.Forms (in System.Windows.Forms.dll)
If no text is selected in the control, this property indicates the insertion point, or caret, for new text. If you set this property to a location beyond the length of the text in the control, the selection start position will be placed after the last character. When text is selected in the text box control, changing this property might decrease the value of the SelectionLength property. If the remaining text in the control after the position indicated by the property is less than the value of the SelectionLength property, the value of the SelectionLength property is automatically decreased. The value of the property never causes an increase in the SelectionLength property.
You can programmatically move the selection within the text box by setting the and the SelectionLength properties.
You can programmatically move the caret within the text box by setting the to the position within the text box where you want the caret to move to and set the SelectionLength property to a value of zero (0).
The following code example uses TextBox, a derived class. It provides Click event handlers for MenuItem objects that perform Cut, Copy, Paste, and Undo operations. This example requires that a TextBox control named textBox1 has been created.
Private Sub Menu_Copy(sender As System.Object, e As System.EventArgs) ' Ensure that text is selected in the text box. If textBox1.SelectionLength > 0 Then ' Copy the selected text to the Clipboard. textBox1.Copy() End If End Sub Private Sub Menu_Cut(sender As System.Object, e As System.EventArgs) ' Ensure that text is currently selected in the text box. If textBox1.SelectedText <> "" Then ' Cut the selected text in the control and paste it into the Clipboard. textBox1.Cut() End If End Sub Private Sub Menu_Paste(sender As System.Object, e As System.EventArgs) ' Determine if there is any text in the Clipboard to paste into the text box. If Clipboard.GetDataObject().GetDataPresent(DataFormats.Text) = True Then ' Determine if any text is selected in the text box. If textBox1.SelectionLength > 0 Then ' Ask user if they want to paste over currently selected text. If MessageBox.Show("Do you want to paste over current selection?", _ "Cut Example", MessageBoxButtons.YesNo) = DialogResult.No Then ' Move selection to the point after the current selection and paste. textBox1.SelectionStart = textBox1.SelectionStart + _ textBox1.SelectionLength End If End If ' Paste current text in Clipboard into text box. textBox1.Paste() End If End Sub Private Sub Menu_Undo(sender As System.Object, e As System.EventArgs) ' Determine if last operation can be undone in text box. If textBox1.CanUndo = True Then ' Undo the last operation. textBox1.Undo() ' Clear the undo buffer to prevent last action from being redone. textBox1.ClearUndo() End If End Sub
Public Class Form1 Private Sub ButtonClickWork(ByVal sender As System.Object, ByVal e As System.EventArgs) _ Handles Button1.Click Me.TextBox1.Text = "Hello world!" Me.TextBox1.ReadOnly = True Me.TextBox1.Focus() Me.TextBox1.SelectionStart = Me.TextBox1.SelectionStart + 1 Me.TextBox1.SelectionLength = 1 End Sub End Class
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.