GridView SortExpression issue

Question

I set the sort expression for a column in a grid view. Then sort the column by clicking on Header. Upto this point fine.

However, when I select a gridView row using the select button which is autogenerated:

<asp:GridView runat="server" ID="test" DataSourceID="sourceEmployees"
 AutoGenerateSelectButton="true">

After selecting a row if I sort the Column by clicking on Header, the GridView still has the old row selected. The intially selected value is lost. If i Select employeeID value 7, the 7th row remains selected even when I sort the Column in descending order, Although my employeeId value 7 has moved to different row. [ here its moved to 4th row as I have total 10 employees ]

What more I need to implement to make sure No matter the way user sorts the GridView, always the initially selected employeeID remains selected.

Are you using custom sorting code, or just the default sorting functionality of the GridView? If custom, could you show that code here in the question? — Josh Darnell
I'm using default sorting. AllowSorting="true" . I just showed only relevant portions of my gridview markup — R.C

Icarus Icarus · Accepted Answer · 2013-08-05T16:09:47

You need to handle everything on the code behind (selecting/deselecting the row when the index changes). Here's an example based on your set up:

<asp:GridView DataKeyNames="EmpID"  
     SelectedRowStyle-BackColor="Yellow" ID="test" OnSelectedIndexChanged="test_SelectedIndexChanged" 
     runat="server" DataSourceID="sourceEmployees" AutoGenerateColumns="False"  
     AutoGenerateSelectButton="true" AllowSorting="true" 
     OnRowDataBound="test_RowDataBound" >

Above, I added two event handlers, one for OnRowDataBound and one for OnSelectedIndexChanged. I also added the DataKey to keep track of the selected employee ID.

Now, on code behind, the for those 2 methods looks like this:

protected void test_SelectedIndexChanged(object sender, EventArgs e)
{
    ViewState["key"]= test.SelectedDataKey.Value;//Keep track of selected employee by ID            
}

protected void test_RowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        var row = e.Row.DataItem as DataRowView;
        if (row.Row.Field<int>("EmpID") == (ViewState["key"] != null ? (int)ViewState["key"] : -1))
        {
            test.SelectedIndex = e.Row.RowIndex;
            //Setting the selected Index is not enough, you need to programmatically
            //set the color as well. Since I used Yellow on my markup, I use the same here
            e.Row.BackColor = System.Drawing.Color.Yellow;
        }

    }
}

GridView SortExpression issue

2 Answers