prevent a row from being deleted in datagrid/datatable

  • Thread starter Thread starter Ryan Liu
  • Start date Start date
R

Ryan Liu

Can someone give a sample to prevent a row from being deleted in a
datatable?

I tried e.Row.RejectChanges(); in dt_RowDeleting() but seems does not work.

I need verify if there other data using data in this row before actually
remove it from datagrid.

I can certainly control with Delete button. But if I want to allow the user
to use Del key on the keyboard, I lost this kind control.

Thanks,
Ryan Liu
 
I tried dt_RowDeleted() , but does not work really well.

The row still "disappear" from datagrid, even it is in datatable.

Even I try to set data grid's DataSource back again or call
dataGrid.Refresh(), or sort the grid,
neither way helps.

The row is still "seems" deleted from the datagrid, I mean, not visible.

But when I click the datagrid "existing data area", the missing row come
back!!

So now I need somehow make a fake mouse click to simulate this action. I
haven't finger out how yet.

By the way, I find I ofter need do this kind of fake action in code. I
thought EndEdit() could help, but does not.

For example, I want something to happen when the user click on a cell. But
Mouse event is not always fired if the current cell hasn't changed, I need
change current cell to someother cell in my code to make mouse down event
always triggered.

Another example is, when I try to move a row up and down in a datagrid, it
does not work well if there is a cell is seleted(even this column is read
only), I need use code to select whole line so no CurrentCell selected.

Oh, there is another thing, to get data in a deleted datarow, I forget to
use DataRowVersion, so there was an exception. But this exception is not
"throw" in the event dt_RowDeleted( ), it is an slient exception!! Take me a
while to find out the mysterious behavior.


private void dt_RowDeleted(object sender, DataRowChangeEventArgs e)
{
int id= (int)e.Row["id", DataRowVersion.Original];

if(id >5)
{
e.Row.RejectChanges();
MessageBox.Show(this, "Can not delete!"); //this worked,
message showed

//this.dataGrid.DataSource = this.dt.DefaultView; //set
DataSource again, but does not help
//this.dataGrid.Refresh();
//does not help
//this.dt.DefaultView.Sort = "id ASC"; //does
not help
}

}

Thanks,
Ryan Liu
 
Ryan,

Is there any reason that you added that Original version tests.

I assume that the Original row will never been deleted. How the update can
than check if there are changes in the database and therefore concurrency
errors. There will be copies made, if you make an XML file you can write
those with the option for that.

I hope this helps,

Cor
 
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