Sometimes you need to access a control within a GridView, but it isn’t quite as straight forward as just using FindControl to grab the control like you
can in a FormView. Since the GridView builds multiple rows the key
is to specify the row. In this example
there is a GridView with a control for a player’s errors. If the errors
is greater than 9 the GridView should display the control (lblErrors) in red so it stands out. Here
is the GridView:
<asp:GridView ID="gvFielding" runat="server" DataSourceID="sqlFielding" DataKeyNames="PlayerID" AutoGenerateColumns="false" >
<Columns>
<asp:BoundField DataField="PlayerName" HeaderText="Player Name" />
<asp:BoundField DataField="PlayerNumber" HeaderText="Player Number" />
<asp:TemplateField HeaderText="Errors">
<ItemTemplate>
<asp:Label ID="lblErrors" runat="server" Text='<%# EVAL("Errors") %>' />
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
In the code behind you
can add the code to change the label’s ForeColor property to red based on the amount of errors. In this case 10 or more errors triggers the color change.
Protected Sub gvFielding_DataBound(ByVal sender As Object, ByVal e As System.EventArgs) Handles gvFielding.DataBound
Dim errorLabel As Label
Dim errors As Integer
Dim i As Integer = 0
For Each row As GridViewRow In gvFielding.Rows
errorLabel = gvFielding.Rows(i).FindControl("lblErrors")
If Not errorLabel.Text =
Nothing Then
Integer.TryParse(errorLabel.Text, errors)
If errors > 9 Then
errorLabel.ForeColor = Drawing.Color.Red
End If
End If
i += 1
Next
End Sub
The main points in the DataBound sub
is use a For Each statement to loop through the rows and to increment the variable i so you loop through every row. That way you check each one and if the value
is greater than 9 the label changes to red. The If Not errorLabel.Text =
Nothing line
is there as a check in case no data comes back at all for Errors.
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