DataTable Cancel Row Delete

Question

I have a windows form which has a DataGrid control (Not DataGridView) on it.

The DataGrid control is bound to a DataTable. Everytime the user presses the delete button on one of the rows on the grid, I want to check a condition and stop the row from being deleted if the condition is false.

I have subscribed to the RowDeleting event of the DataTable, but i cant find a way to cancel to the delete operation performed by the user. How can i achieve this ?

Answer 1

Although this thread is 2 years old, I add the answer just in case someone stumbles across.

For each row in a DataTable, there is method "RejectChanges()", which you can use to undo a delete.

I did as follows:

a) To the DataTable, add a "RowDeleted" Handler:

dt.RowDeleted += new DataRowChangeEventHandler(dt_RowDeleted);

b) In the handler, call the functon "RejectChanges()" as follows:

void dt_RowDeleted(object sender, DataRowChangeEventArgs e)
{
     if ( ... Add your condition here ... ) 
         e.Row.RejectChanges();
}

Answer 2

Much easier than the above solutions.

In the UserDeletingRow event just call e.Cancel = true;

DialogResult dlgRes = MessageBox.Show("Are you sure that you want to delete this Factor?", "DELETE ITEM?", MessageBoxButtons.YesNo, MessageBoxIcon.Warning);
if (dlgRes == DialogResult.Yes)
{
    //WBSDA.Delete(dgvR.Cells["WBSID"].Value.ToInt());
    tslMessage.Text = "Item Deleted";
}
else
    e.Cancel = true;

Answer 3

Rubens

Thanks for you response. I had already looked up that thread, but couldnt find a useful solution.

I just slightly modified my project, I now have a delete button instead of deleting directly from the datagrid itself.

I changed my DataTable to disallow any deletes

dataTable.DefualtView.AllowDelete = false

and in the delete button click handler, i wrote the following code:

(datagridStandardRates.DataSource as DataTable).Rows[datagridStandardRates.CurrentRowIndex].Delete();

This gives me complete control over when I want to delete a row.

Thanks once again for your help.

Raghu

Answer 4

My first thought was to suggest "e.Cancel = true;" but that property isn't available.

Googling a bit I came across How do I cancel a row delete in a DataSet ; please, take a look.

HTH