You can use this property to determine if the user has modified the contents of the text box control. You can also set this property in code to indicate that changes were made to the text box control by the application. This property can be used by validation and data-saving methods to determine if changes were made in a text box control so the changed contents can be validated or saved.

If you change the Text property programmatically, the Modified property reverts to false. This does not raise the ModifiedChanged event.

The following code example uses the TextChanged event for a TextBox, a derived class, to determine if the contents of the TextBox control have changed since the control was filled with data. The example uses a string to store the original contents of the control and compares it against the contents of the TextBox to determine if the contents have changed. If the contents have changed, the Modified property is set to true. Otherwise, it is reset to false. This example requires that a TextBox control named textBox1 has been created and that a String variable named originalText has been created to store the original text for the TextBox control.

Private Sub TextBox1_TextChanged(sender As Object, e As EventArgs)
    ' Check to see if the change made does not return the
    ' control to its original state. 
    If originalText <> textBox1.Text Then
        ' Set the Modified property to true to reflect the change.
        textBox1.Modified = True
        ' Contents of textBox1 have not changed, reset the Modified property.
    Else
        textBox1.Modified = False
    End If
End Sub

private void TextBox1_TextChanged(object sender, EventArgs e)
 {
    /* Check to see if the change made does not return the
       control to its original state. */
    if (originalText != textBox1.Text)
       // Set the Modified property to true to reflect the change.
       textBox1.Modified = true;
    else
       // Contents of textBox1 have not changed, reset the Modified property.
       textBox1.Modified = false;
 }

private:
   void TextBox1_TextChanged( Object^ sender, EventArgs^ e )
   {
      /* Check to see if the change made does not return the
         control to its original state. */
      if ( originalText != textBox1->Text )
      {
         // Set the Modified property to true to reflect the change.
         textBox1->Modified = true;
      }
      else
      {
         // Contents of textBox1 have not changed, reset the Modified property.
         textBox1->Modified = false;
      }
   }

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, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC

.NET Framework

.NET Compact Framework

Reference