KeyPress事件处理程序方法未执行

Question

I have written the following code for the DataGridView KeyPress which is not executed in VS 2010:

private void DataGridView1_KeyPress(object sender, KeyPressEventArgs e)
    {
         MessageBox.Show("Entering DataGridView Key Press event");
    }

When I press keys in any of the cells of the DataGridView, this method is not getting executed. Can anyone tell me where I might be wrong?

I have written the following code. Code gets executed on the specified cell only but it is always executing the else part even though I press a Number key. Else part is executed twice for a single key press event.

private void MatCompDtlDataGridView_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
    {
        DataGridViewTextBoxEditingControl tb = (DataGridViewTextBoxEditingControl)e.Control;
        //tb.KeyPress += new KeyPressEventHandler(dataGridViewTextBox_KeyPress);
        e.Control.KeyPress += new KeyPressEventHandler(dataGridViewTextBox_KeyPress);
    }
    private void dataGridViewTextBox_KeyPress(object sender, KeyPressEventArgs e)
    {
        DataGridViewRow CurrentRow = new DataGridViewRow();
        CurrentRow = MatCompDtlDataGridView.CurrentRow;
        if ((CurrentRow.Index != -1) && (MatCompDtlDataGridView.CurrentCell.ColumnIndex == txtQtyDGV.Index))
        {
            if (!char.IsControl(e.KeyChar)
            && !char.IsDigit(e.KeyChar)
            && (sender as TextBox).Text.IndexOf('.') > -1)
            {
                e.Handled = true;
            }
            else
            {
                e.Handled = false;
                MessageBox.Show("You can only enter Digits and a single Decimal Point. Maximum number of digits on the left side of the decimal point can be four and on the right hand side three");
            }
        }

Answer 1

Key press events when you are editing content in a cell does not come through the DataGridView's KeyPress event. You will need to either handle the KeyPress event directly on the editing control (you can get the editing control in the EditingControlShowing event). Alternatively you can derive from the DataGridView and override the ProcessDialogKey method which will get called for key events on the editing control.

Add the following line to form's constructor

public Form1()
{
   InitializeComponent();    
   dataGridView1.EditingControlShowing += new DataGridViewEditingControlShowingEventHandler(dataGridView1_EditingControlShowing);    
}

dataGridView1_EditingControlShowing event

void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
{
   dataGridView1.EditingControl.TextChanged += new EventHandler(EditingControl_TextChanged);
}

EditingControl_TextChanged event

void EditingControl_TextChanged(object sender, EventArgs e)
{
   //Capturing the value typed into grid's cell
   string text = dataGridView1.EditingControl.Text;
}

Answer 2

be sure your DGV isn't read only, and then try something like:

  private void dataGridView1_EditingControlShowing(object sender, 
        DataGridViewEditingControlShowingEventArgs e)
    {
       MessageBox.Show("Entering DataGridView Key Press event");
  }

Answer 3

Your current validation logic look a bit off. You can't be sure that the cell value is a valid decimal value -with specified format- by only checking currently pressed key. I think following sample is closer to what you want :

//only allow number and decimal separator
if(char.IsDigit(e.KeyChar) || e.KeyChar == '.')
{
    //curren text in cell
    var previousText = (sender as TextBox).Text;
    //cell content after the pressed key char appended
    var nextText = previousText + e.KeyChar.ToString();
    //validate cell content to make sure the format comply
    if(ValidateText(nextText)) e.Handled = true;
    else
    {
        //what to do if it doesn't comply
    }
}
else
{
    e.Handled = false;
    MessageBox.Show("You can only enter Digits and a single Decimal Point. Maximum number of digits on the left side of the decimal point can be four and on the right hand side three");
}

private bool ValidateText(string cellText)
{
    //TODO: put your validation logic here to ensure that..
    //Maximum number of digits on the left side of the decimal point can be four and on the right hand side three
}