Follow these steps to make a DataGrid editable:
1. Add <asp:EditCommandColumn ...> to your .aspx file. This just gives you
the column with hyperlinks - nothing else.
2. Next you add the EditCommand event handler. You add event handlers from
the properties window for the DataGrid. Click the lighning bolt at the top
of the properties window to display all of the possible events. Double
click the EditCommand event. This automatically adds the following function
to your codebehind file. You need to fill in the body as I have done below.
e.Item.ItemIndex gives you the number of the row where you selected "edit".
Setting the EditItemIndex property is what actually makes the row editable.
Then you bind to the data.
private void DataGrid1_EditCommand(object source,
System.Web.UI.WebControls.DataGridCommandEventArgs e)
{
DataGrid1.EditItemIndex = e.Item.ItemIndex;
DataGrid1.Databind();
}
3. At this point your application can put the grid into edit mode for any of
the rows. You next need to add an event handler for the CancelCommand just
as you did for the EditCommand above. The CancelCommand event should be
implemented as follows:
private void DataGrid1_CancelCommand(object source,
System.Web.UI.WebControls.DataGridCommandEventArgs e)
{
DataGrid1.EditItemIndex = -1;
DataGrid1.Databind();
}
Setting EditItemIndex to -1 causes the grid to display with no rows
editable.
4. Next add a event handler for the UpdateCommand event. This is the most
complicated because you must get the modified data from the grid and update
the database. An example of this is as follows.
private void DataGrid1_UpdateCommand(object source,
System.Web.UI.WebControls.DataGridCommandEventArgs e)
{
TextBox tb = (TextBox)(e.Item.Cells[0].Controls[0]);
int nID = System.Int32.Parse(tb.Text);
tb = (TextBox)(e.Item.Cells[1].Controls[0]);
string sName = tb.Text;
/* PERFORM UPDATE HERE
..........................................................
*/
DataGrid1.EditItemIndex = -1;
BindGrid();
}
In my example above, the grid contains an ID and a Name. They are both
displayed in the grid. It's easy to extract these and update the database.
In your case, you don't want to display the ID column or edit it, but you
need access to it in the UpdateCommand event handler. This is very common.
What you need to do is set the DataKeyField property to the name of the
column. You can do this in the properties page for the grid or by editing
the grid properties manually in the .aspx. This will cause the keys to be
saved to the DataGrid's DataKeys collection grid when the data is bound.
You would need to access this data in your UpdateCommand Event Handler as
follows:
string sTemp = DataGrid1.DataKeys[e.Item.ItemIndex].ToString();
nID = System.Int32.Parse(sTemp);
Now you have the "hidden" data that you need to update the database.
Good luck
Mark,
Thanks for the feedback. In regular windows development this is such a no
brainer, but life goes on. Anyway, can I stick with my current
implementation using the SQLDataReader to load the grid??
Also, is there a quick and easy way for me to access the column to copy what
I need to update?
If I understand you correctly, you are saying get what you need to update
from the grid and then run an update query to write the data back to the
database. As it stands right now, I can put the Edit, Update, Cancel button
on the grid and can get the button to fire, but the grid is read only.
Is
is
read only becuase of a property setting or because I am using a datareader
as the data source.
Thanks Again for your time.
Michael
Mark Schubert said:
Include the unique key column for the order items table in the query that
joins the two tables. Set the Datagrid's DataKeyField property to the name
of the key column. You do not need to display this column. In the
Datagrid's Update event handler, use the DataKeys collection to
retrieve
the
key for the order item record that you want to update as follows:
string sTemp = DataGrid1.DataKeys[e.Item.ItemIndex].ToString();
nID = System.Int32.Parse(sTemp);
Once you have the key you can run an update statement against just order
item record with that key.
Hi,
I have a datagrid that shows data joined from multiple tabes and works
just
fine. I load it with a SQLDataReader, and all was great.
Now I need to allow update of the data strickly in one of the joined
tables.
Example:
Orders and Order Items are the Join. In the grid would be column heading
similar to:
Customer Name Item Number Item Name Qty
This is not exactly what I am trying to do but in the example I
would
like
to enable the user to be able to update the Item Number (a field in the
OrderItems Table).
All information I have found so far keys on the fact that the
datagrid
is
based on a DataAdapter/Dataset based on one table--simple but not
realistic.
Any pointers would be appreciated.
Regards,
Michael Murphy
(e-mail address removed)
954-452-1047
