How to loop through GridView rows which have EditItemTemplates

Question

I have a function which loops through all the rows of my GridView and compares some of the cell values with a value the user wants to insert into the table. The point is to make sure the value they want to insert is not a duplicate value.

This function was working fine until I recently made most of the columns into EditItemTemplate controls so that I could access them on update.

Now, depending on how I try to do it, I either get a blank string or I get a "Object reference not set to an instance of an object" error.

Here's how I was originally finding the specific cell (which now apparently does nothing):

GridView1.Rows[rowIndex].Cells[2].Text

And here's how I'm doing it now (but which gives me the reference error):

GridView1.FindControl("storeNumberTB").ToString()

I suspect the issue is that I'm referencing a TextBox control within EditItemTemplate rather than just the label(?) which is what I presumably need to look at as I loop through the rows. But I can't figure out how to access the value.

So I just need to get whatever text is at a particular cell on every row as it loops through.

Here's the entire function as it is now in case that helps:

foreach (GridViewRow row in GridView1.Rows)
        {
          if (GridView1.FindControl("storeNumberTB").ToString() == userInputValue)
          {
            duplicate++;
          }
        }

Here's the relevant part of my ASPX code for the GridView:

 <asp:TemplateField HeaderText="Store">
                <ItemTemplate >
                    <asp:Label runat="server" Text='<%# Eval("Store") %>' >
                    </asp:Label>
                </ItemTemplate>
                <EditItemTemplate >
                    <asp:TextBox ID="storeNumberTB" runat="server" Text='
                    <%# Eval("Store")%>'  ></asp:TextBox>
                </EditItemTemplate>
           </asp:TemplateField>

UPDATE: row.Cells[3].Text returns an empty string. No clue why. Any idea how to access the value in the cell in my case?

when you have the added stuff in the GridView does that throw the columns count off.. for example Cell[2] would be Cell[3] and so on and so forth.. — MethodMan, Nov 27 '17 at 19:40
MethodMan: I don't know why it would. Same number of columns. — Sherlock, Nov 27 '17 at 19:49

Salvador Ruiz Guevara · Answer 1 · 2017-11-27T20:16:30.427

2

You need to use the FindControl in the GridViewRow, not in the full control.

row.FindControl("abc")..

Also you will need to cast it to the proper control.

-Update. Misunderstood the OP question.

foreach (GridViewRow row in GridView1.Rows)
{

    var label = row.FindControl("labelname") as Label;
    ....your code...
}

Important: Also name your label. The asp:Label has no id.

edited Nov 27 '17 at 20:16

answered Nov 27 '17 at 19:34

Salvador Ruiz Guevara

184
2
15

This is still giving me the same object reference error. – Sherlock Nov 27 '17 at 19:45
Did you cast the Findcontrol resulting object as a Textbox? – Salvador Ruiz Guevara Nov 27 '17 at 19:48
Yes. But am I actually looking for a textbox anyway? I'm looping through the GridView while it isn't in edit mode, so wouldn't they just be labels? I also tried casting them as labels. – Sherlock Nov 27 '17 at 19:50
Oh ok...i misunderstood your question. Then you dont need the FindControl.Will edit my answer – Salvador Ruiz Guevara Nov 27 '17 at 20:07
Ugh...did not see that you updated your question. will edit again. – Salvador Ruiz Guevara Nov 27 '17 at 20:12
Thanks. However, this does not seem to be retrieving any value either. I am really at wit's end about this. Nothing seems to be working as expected. – Sherlock Nov 27 '17 at 20:13
strange..been a while since i did aspx. Only reason it should be null would be if the iteration goes thru the header and footer rows too. If all the rows are in read mode only, the label should be in all of them . – Salvador Ruiz Guevara Nov 29 '17 at 16:36

score 0 · Answer 2 · answered Nov 27 '17 at 19:52

0

In the foreach loop, you should use the row iterator. And I'm guessing you need to find the control and cast it as a textbox before you can get it's value. Something like this

foreach (GridViewRow row in GridView1.Rows)
{
    TextBox txtStoreNumber = row.Cells[2].FindControl("storeNumberTB") as TextBox;
    if (txtStoreNumber.Text == userInputValue)
    {
        duplicate++;
    }
}

answered Nov 27 '17 at 19:52

Mohamed Najiullah

403
5
12

But I don't think what I'm looking for is actually a Text Box? I'm afraid my explanation was unintentionally confusing. I'm trying to just loop through the GridView. The reason I even mentioned the TextBox controls is because my duplicate check stopped working once I added the TextBox controls, which makes no sense to me. It's like it wants me to access the TextBox controls, but when I try to do that, it gives me an object reference error (presumably because the loop is not looking at the TextBoxes because nothing is in edit mode), but if I try to loop through normally, nothing happens. – Sherlock Nov 27 '17 at 20:17
https://stackoverflow.com/questions/14584175/how-to-find-control-in-edit-item-template does this help? – Mohamed Najiullah Nov 27 '17 at 20:20
I don't if I'm just missing something or what. But I cannot figure out what the issue is. I tried doing row.Cells[3].Text and it returned an empty string. It seems whatever I do I either get an empty string, an object reference error, or I get a string that says something like "WebControls.CellFieldData" (can't remember exactly what it said, but something like that). – Sherlock Nov 27 '17 at 23:51

score 0 · Answer 3 · answered Nov 28 '17 at 09:48

0

try with

GridViewRow row = (GridViewRow)((Button)sender).NamingContainer;
TextBox TextBox1 = row.FindControl("storeNumberTB") as TextBox; 
string storeNumberTBtext= TextBox1.Text;

answered Nov 28 '17 at 09:48

user7415073

290
4
22

How to loop through GridView rows which have EditItemTemplates

3 Answers3