Private Sub TextBox1_Validating(ByVal sender As Object, _
ByVal e As System.ComponentModel.CancelEventArgs) _
Handles TextBox1.Validating

    ' If nothing is entered,
    ' an ArgumentException is caught; if an invalid directory is entered, 
    ' a DirectoryNotFoundException is caught. An appropriate error message 
    ' is displayed in either case.
    Try
        Dim directory As New System.IO.DirectoryInfo(TextBox1.Text)
        directory.GetFiles()
        ErrorProvider1.SetError(TextBox1, "")

    Catch ex1 As System.ArgumentException
        ErrorProvider1.SetError(TextBox1, "Please enter a directory")

    Catch ex2 As System.IO.DirectoryNotFoundException
        ErrorProvider1.SetError(TextBox1, _
        "The directory does not exist." & _
        "Try again with a different directory.")
    End Try

End Sub

' This method handles the LostFocus event for TextBox1 by setting the 
' dialog's InitialDirectory property to the text in TextBox1.
Private Sub TextBox1_LostFocus(ByVal sender As Object, _
    ByVal e As System.EventArgs) Handles TextBox1.LostFocus
    OpenFileDialog1.InitialDirectory = TextBox1.Text
End Sub


' This method demonstrates using the ErrorProvider.GetError method 
' to check for an error before opening the dialog box.
Private Sub Button1_Click(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles Button1.Click

    'If there is no error, then open the dialog box.
    If ErrorProvider1.GetError(TextBox1) = "" Then
        Dim dialogResult As DialogResult = OpenFileDialog1.ShowDialog()
    End If

End Sub

    private void textBox1_Validating(object sender, 
        System.ComponentModel.CancelEventArgs e)
    {
        // If nothing is entered,
        // an ArgumentException is caught; if an invalid directory is entered, 
        // a DirectoryNotFoundException is caught. An appropriate error message 
        // is displayed in either case.
        try
        {
            System.IO.DirectoryInfo directory = 
                new System.IO.DirectoryInfo(textBox1.Text);
            directory.GetFiles();
            errorProvider1.SetError(textBox1, "");

        }
        catch(System.ArgumentException ex1)
        {
            errorProvider1.SetError(textBox1, "Please enter a directory");

        }
        catch(System.IO.DirectoryNotFoundException ex2)
        {
            errorProvider1.SetError(textBox1, "The directory does not exist." +
                "Try again with a different directory.");
        }

    }

    // This method handles the LostFocus event for textBox1 by setting the 
    // dialog's InitialDirectory property to the text in textBox1.
    private void textBox1_LostFocus(object sender, System.EventArgs e)
    {
        openFileDialog1.InitialDirectory = textBox1.Text;
    }

    // This method demonstrates using the ErrorProvider.GetError method 
    // to check for an error before opening the dialog box.
    private void button1_Click(System.Object sender, System.EventArgs e)
    {
        //If there is no error, then open the dialog box.
        if (errorProvider1.GetError(textBox1)=="")
        {
            DialogResult dialogResult = openFileDialog1.ShowDialog();
        }
    }

private:
   void TextBox1_Validating( Object^ sender,
      System::ComponentModel::CancelEventArgs^ e )
   {
      // If nothing is entered,
      // an ArgumentException is caught; if an invalid directory is entered, 
      // a DirectoryNotFoundException is caught. An appropriate error message 
      // is displayed in either case.
      try
      {
         System::IO::DirectoryInfo^ directory = gcnew System::IO::DirectoryInfo( TextBox1->Text );
         directory->GetFiles();
         ErrorProvider1->SetError( TextBox1, "" );
      }
      catch ( System::ArgumentException^ ) 
      {
         ErrorProvider1->SetError( TextBox1, "Please enter a directory" );
      }
      catch ( System::IO::DirectoryNotFoundException^ ) 
      {
         ErrorProvider1->SetError( TextBox1, "The directory does not exist."
         "Try again with a different directory." );
      }
   }

   // This method handles the LostFocus event for TextBox1 by setting the 
   // dialog's InitialDirectory property to the text in TextBox1.
   void TextBox1_LostFocus( Object^ sender, System::EventArgs^ e )
   {
      OpenFileDialog1->InitialDirectory = TextBox1->Text;
   }

   // This method demonstrates using the ErrorProvider.GetError method 
   // to check for an error before opening the dialog box.
   void Button1_Click( System::Object^ sender, System::EventArgs^ e )
   {
      //If there is no error, then open the dialog box.
      if ( ErrorProvider1->GetError( TextBox1 )->Equals( "" ) )
      {
         ::DialogResult dialogResult = OpenFileDialog1->ShowDialog();
      }
   }

private void textBox1_Validating(Object sender, 
    System.ComponentModel.CancelEventArgs e)
{
    // If nothing is entered,
    // an ArgumentException is caught; if an invalid directory is entered, 
    // a DirectoryNotFoundException is caught. An appropriate error message 
    // is displayed in either case.
    try {
        System.IO.DirectoryInfo directory = new System.IO.DirectoryInfo(
            textBox1.get_Text());
        directory.GetFiles();
        errorProvider1.SetError(textBox1, "");
    }
    catch (System.ArgumentException ex1) {
        errorProvider1.SetError(textBox1, "Please enter a directory");
    }
    catch (System.IO.DirectoryNotFoundException ex2) {
        errorProvider1.SetError(textBox1, "The directory does not exist." 
            + "Try again with a different directory.");
    }
} //textBox1_Validating

// This method handles the LostFocus event for textBox1 by setting the 
// dialog's InitialDirectory property to the text in textBox1.
private void textBox1_LostFocus(Object sender, System.EventArgs e)
{
    openFileDialog1.set_InitialDirectory(textBox1.get_Text());
} //textBox1_LostFocus

// This method demonstrates using the ErrorProvider.GetError method 
// to check for an error before opening the dialog box.
private void button1_Click(Object sender, System.EventArgs e)
{
    //If there is no error, then open the dialog box.
    if (errorProvider1.GetError(textBox1).Equals("")) {
        DialogResult dialogResult = openFileDialog1.ShowDialog();
    }
} //button1_Click