Get values from GridView

Question

I have a GridView that is populated by a service and I have added a link on each line of this grid so that I may take action when that specific row is clicked. I want to get some of the items in the selected row but even if I add a onSelectedRowChanged event I am not getting that event to fire, just my link.

<asp:GridView ID="gvTransactionHistory" runat="server" 
    AutoGenerateColumns="false"  
    onselectedindexchanging="gvTransactionHistory_SelectedIndexChanging">
    <Columns>
        <asp:TemplateField>
            <ItemTemplate>
                <asp:Label ID="lblAmount" runat="server" Text='<%# Eval("preAuthAmount") %>'></asp:Label>
                <asp:LinkButton runat="server" Text="Assign+" OnClick="btnAssign"></asp:LinkButton>
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>

Here is my btnAssign click event, which works fine...

protected void btnAssign(object sender, EventArgs e)
{
    Response.Write("Works!");
}

I added this to see if I could trigger this event but I am not really changing index so what I need help with is understanding what event I can tie into that will allow me to click my link button, and get the values from THAT row.

protected void gvTransactionHistory_SelectedIndexChanging(object sender, System.Web.UI.WebControls.GridViewSelectEventArgs e)
{
    var amount = gvTransactionHistory.SelectedRow.Cells[3].Text;
    Response.Write(amount);
}

Karl Anderson · Accepted Answer · 2013-10-10 18:23:15Z

4

To use the btnAssign click event handler to get the row, then you need to get the NamingContainer (read: parent) of the button that was clicked, like this:

protected void btnAssign(object sender, EventArgs e)
{
    GridViewRow theClickedRow = ((LinkButton)sender).NamingContainer as GridViewRow;

    // Check to make sure the clicked row could be found before using it
    if(theClickedRow != null)
    {
        // Find the amount label control
        Label theAmountLabel = theClickedRow.FindControl("lblAmount") as Label;

        // Again, make sure we actually have something before using it
        if(theAmountLabel != null)
        {
            // Get the actual label's text here
            string theAmountLabelText = theAmountLabel.Text;
        }
    }
}

edited Oct 10, 2013 at 18:23

answered Oct 10, 2013 at 18:02

Karl Anderson

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2 Comments

user2146538 Over a year ago

Karl, that got me the row but when I try to do something like get the field, for example, var amount = theClickedRow.Cells[0].Text; I get empty text despite the data being rendered. I like this approach but I guess I am missing something....

Karl Anderson Over a year ago

@user2146538 - Use FindControl() to get to the server control, see updated answer.

Smeegs · Accepted Answer · 2013-10-10 20:25:33Z

1

I know the question has already been answered, but I figured I'd give an alternate option.

You can always add attributes to server controls, and just pull them later.

For example, I can add the preAuthAmount to the link button as an attribute named "preAuthAmount".

<asp:Label ID="lblAmount" runat="server" Text='<%# Eval("preAuthAmount") %>'></asp:Label>
<asp:LinkButton runat="server" Text="Assign+" preAuthAmount='<%# Eval("preAuthAmount") %>' itemID='<%# Eval("itemID") %>' OnClick="btnAssign"></asp:LinkButton>

Then just pull the attribute in the click event

protected void btnAssign(object sender, EventArgs e)
{
    string preAuthAmount= ((LinkButton)sender).Attributes["preAuthAmount"];
    string itemID= ((LinkButton)sender).Attributes["itemID"];
}

It's a lot less code and pretty easy to read.

A third option would be to use datakeys

In the markup of the gridview, add all the fields you want to be able to access to the gridview.

<asp:GridView ID="gvTransactionHistory" runat="server" 
    AutoGenerateColumns="false"  
    onselectedindexchanging="gvTransactionHistory_SelectedIndexChanging" 
    DataKeyNames="ID, preAuthAmount, AnyField">

These datakeys can be accessed in the code behind with the row index

protected void btnAssign(object sender, EventArgs e)
{

    var rowIndex = (((LinkButton)sender).NamingContainer as GridViewRow).RowIndex;
    var id = gvTransactionHistory.DataKeys[rowIndwx].Values["ID"];
    var preAuthAmount = gvTransactionHistory.DataKeys[rowIndwx].Values["preAuthAmount"];
}

The issue with the other answer is that it's a bit unstable. The "findcontrol" method only looks for direct descendants, and may not always work.

edited Oct 10, 2013 at 20:25

answered Oct 10, 2013 at 19:05

Smeegs

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3 Comments

user2146538 Over a year ago

Javalsu, also a good suggestion, however, I want to access more than one field in the row. I limited my sample question to one item for simplicity.

Smeegs Over a year ago

There's no limit to the number of attributes you can add. You can add as many fields as you want.

Smeegs Over a year ago

I also added a third option. The findcontrol option works, but it's a bit wonky and can cause issues.

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