Detecting some text has been selected in a textbox

Question

I've implemented a notepad application in c#,all the feaures work perfectly,there is only one thing which I can't implement exactly.there are some menuitems in the edit dropdown menu,but their enabled property must change according to the situation of the textbox,I have a problem with two situations and I'm looking for an event in order to change their enabled property in this event's eventhandler,here is the problem:

2)When some text is selected in the textbox,delete,copy and paste options should get enabled.how should I detect it?I've tested texchanged event an I've written a condition like the code below but it didn't work,just the clipboard works well:

private void textBox1_TextChanged(object sender, EventArgs e)
    {
        if (textBox1.SelectionLength> 0)
            button1.Enabled = false;
        if (Clipboard.ContainsText())
            button2.Enabled = false;


    }

How should I solve my problem,by the way I have to use a textbox not a richtextbox. Any suggestions will be appreciated. Thanks a lot

Answer 1

To find out selection

if (textbox1.SelectionLength > 0)
{

}

For clipboard content, use

System.Windows.Forms.Clipboard.getText();

Check clipboard content by,

IDataObject iData = Clipboard.GetDataObject();
// Is Data Text?
if (iData.GetDataPresent(DataFormats.Text))
    label1.Text = (String)iData.GetData(DataFormats.Text);
else
label1.Text = "Data not found."; 

This is implemented in the code. You can use it directly as above

Most important, don't forget

public virtual string SelectedText { get; set; }

This is the complete code with menu item

private void Menu_Copy(System.Object sender, System.EventArgs e)
{
// Ensure that text is selected in the text box.    
if(textBox1.SelectionLength > 0)
    // Copy the selected text to the Clipboard.
    textBox1.Copy();
}

private void Menu_Cut(System.Object sender, System.EventArgs e)
{   
 // Ensure that text is currently selected in the text box.    
 if(textBox1.SelectedText.Length > 0)
    // Cut the selected text in the control and paste it into the Clipboard.
    textBox1.Cut();
 }

Private void Menu_Paste(System.Object sender, System.EventArgs e)
{
// Determine if there is any text in the Clipboard to paste into the text box. 
if(Clipboard.GetDataObject().GetDataPresent(DataFormats.Text))
{
    // Determine if any text is selected in the text box. 
    if(textBox1.SelectionLength > 0)
    {
      // 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)
         // Move selection to the point after the current selection and paste.
         textBox1.SelectionStart = textBox1.SelectionStart + textBox1.SelectionLength;
    }
    // Paste current text in Clipboard into text box.
    textBox1.Paste();
  }
}


private void Menu_Undo(System.Object sender, System.EventArgs e)
{
// Determine if last operation can be undone in text box.    
if(textBox1.CanUndo == true)
{
   // Undo the last operation.
   textBox1.Undo();
   // Clear the undo buffer to prevent last action from being redone.
   textBox1.ClearUndo();
}
}