CODEWITHSUNDEEP
.netdatagridviewkeyboard-events
Viesturs
Viesturs

Reputation: 1691

How to get keypressed, keydown events from DataGridView data cells

I need to receive the key press events during cell editing in DataGridView control.

From what I have found on the net the DataGridView is designed to pass all key events from DataGridView to the cell editing control and you cannot get these events easily.

I found this piece of code that traps those events for DataGrid control, but that does not work for DataGridView.

Upvotes: 7

Views: 21793

Answers (6)

Jumpster
Jumpster

Reputation:

Or, for those of use that DON'T want to create our own DataGridView for such occassions; there's this method (in C++): It uses the EditingControlShowing Event of the DataGridView.

private: System::Boolean fIsNonNumeric;
private: static System::Windows::Forms::KeyEventHandler^ EventKeyDown = nullptr;
private: static System::Windows::Forms::KeyPressEventHandler^ EventKeyPress = nullptr;
private: System::Void dataGridView_KeyDown(System::Object^  sender, System::Windows::Forms::KeyEventArgs^  e) 
{
  fIsNonNumeric= false;

  // Determine whether the keystroke is a number from the top of the keyboard.
  if ( e->KeyCode < Keys::D0 || e->KeyCode > Keys::D9 )
  {
    // Determine whether the keystroke is a number from the keypad.
    if ( e->KeyCode < Keys::NumPad0 || e->KeyCode > Keys::NumPad9 )
    {
      // Determine whether the keystroke is a backspace.
      if ( e->KeyCode != Keys::Back )
      {
        // A non-numerical keystroke was pressed.
        // Set the flag to true and evaluate in KeyPress event.
        fIsNonNumeric = true;
      }
    }
  }
}

private: System::Void dataGridView_KeyPress(System::Object^  sender, System::Windows::Forms::KeyPressEventArgs^  e) 
{
  // Should we stop the character from being entered...?
  if ( fIsNonNumeric == true )
    e->Handled = true;
}

private: System::Void dataGridView_Machines_EditingControlShowing(System::Object^  sender, System::Windows::Forms::DataGridViewEditingControlShowingEventArgs^  e) 
{
  if (nullptr == EventKeyDown)
    EventKeyDown = (gcnew System::Windows::Forms::KeyEventHandler( this, &ProjectForm::dataGridView_KeyDown ));

  if (nullptr == EventKeyPress)
    EventKeyPress = (gcnew System::Windows::Forms::KeyPressEventHandler( this, &ProjectForm::dataGridView_KeyPress ));

  e->Control->KeyDown -= EventKeyDown;
  e->Control->KeyPress -= EventKeyPress;

  e->Control->KeyDown += EventKeyDown;
  e->Control->KeyPress += EventKeyPress;
}

Upvotes: 2

Viesturs
Viesturs

Reputation: 1691

Finally figured out. There are two parts of this puzzle - getting keys from cell editing control and getting keys from the DataGridView itself. Here's my code. To use it, you just need to subscribe to the custom event: keyPressHook.

class KeyPressAwareDataGridView : DataGridView
{

    protected override void OnControlAdded(ControlEventArgs e)
    {
        this.subscribeEvents(e.Control);
        base.OnControlAdded(e);
    }

    protected override void OnControlRemoved(ControlEventArgs e)
    {
        this.unsubscribeEvents(e.Control);
        base.OnControlRemoved(e);
    }

    protected override bool ProcessDataGridViewKey(KeyEventArgs e)
    {
        bool procesedInternally = false;

        if (this.keyPressHook != null)
        {
            this.keyPressHook(this, e);
            procesedInternally = e.SuppressKeyPress;
        }

        if (procesedInternally)
        {
            return true;
        }
        else
        {
            return base.ProcessDataGridViewKey(e);
        }
    }


    private void subscribeEvents(Control control)
    {
        control.KeyDown += new KeyEventHandler(this.control_KeyDown);
        control.ControlAdded += new ControlEventHandler(this.control_ControlAdded);
        control.ControlRemoved += new ControlEventHandler(this.control_ControlRemoved);

        foreach (Control innerControl in control.Controls)
        {
            this.subscribeEvents(innerControl);
        }
    }

    private void unsubscribeEvents(Control control)
    {
        control.KeyDown -= new KeyEventHandler(this.control_KeyDown);
        control.ControlAdded -= new ControlEventHandler(this.control_ControlAdded);
        control.ControlRemoved -= new ControlEventHandler(this.control_ControlRemoved);

        foreach (Control innerControl in control.Controls)
        {
            this.unsubscribeEvents(innerControl);
        }
    }

    private void control_ControlAdded(object sender, ControlEventArgs e)
    {
        this.subscribeEvents(e.Control);
    }

    private void control_ControlRemoved(object sender, ControlEventArgs e)
    {
        this.unsubscribeEvents(e.Control);
    }

    private void control_KeyDown(object sender, KeyEventArgs e)
    {
        if (this.keyPressHook != null)
        {
            this.keyPressHook(this, e);
        }
    }

    public event KeyEventHandler keyPressHook;

}

Upvotes: 2

Viesturs
Viesturs

Reputation: 1691

I found a partial solution by listening to EditingControlShowing and adding key listener to each new editing control.

This gives me access to most of the keys, but I still do not get arrow keys.

I'll try out what Eren Aygunes suggested.

Upvotes: 0

Eren Aygunes
Eren Aygunes

Reputation: 997

Try this:

class KeyPressAwareDataGridView : DataGridView
{
    protected override void OnControlAdded(ControlEventArgs e)
    {
        SubscribeEvents(e.Control);
        base.OnControlAdded(e);
    }

    protected override void OnControlRemoved(ControlEventArgs e)
    {
        UnsubscribeEvents(e.Control);
        base.OnControlRemoved(e);
    }

    private void SubscribeEvents(Control control)
    { 
        control.KeyPress += new KeyPressEventHandler(control_KeyPress);
        control.ControlAdded += new ControlEventHandler(control_ControlAdded);
        control.ControlRemoved += new ControlEventHandler(control_ControlRemoved);

        foreach (Control innerControl in control.Controls)
        {
            SubscribeEvents(innerControl);
        }
    }

    private void UnsubscribeEvents(Control control)
    {
        control.KeyPress -= new KeyPressEventHandler(control_KeyPress);
        control.ControlAdded -= new ControlEventHandler(control_ControlAdded);
        control.ControlRemoved -= new ControlEventHandler(control_ControlRemoved);

        foreach (Control innerControl in control.Controls)
        {
            UnsubscribeEvents(innerControl);
        }
    }

    private void control_ControlAdded(object sender, ControlEventArgs e)
    {
        SubscribeEvents(e.Control);
    }

    private void control_ControlRemoved(object sender, ControlEventArgs e)
    {
        UnsubscribeEvents(e.Control);
    }

    private void control_KeyPress(object sender, KeyPressEventArgs e)
    {
        // Apply your logic here whether this is the key pressed event you need.
        // (e.g. "if(SelectedCells != null)")
        MessageBox.Show(e.KeyChar.ToString());
    }
}

Upvotes: 2

Eyvind
Eyvind

Reputation: 5271

Perhaps not as nice as Mladen Prajdic's answer above, but maybe a little easier, depending on your situation. You may override the ProcessCmdKey method of the form or the control itself, handle keystrokes there, and check for the current cell.

Upvotes: 1

Mladen Prajdic
Mladen Prajdic

Reputation: 15685

you have to override the DataGridViewCell/DataGridViewTextBoxCell/otherTypes and handle key* events in the derived class.

Upvotes: 0

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