CODEWITHSUNDEEP
asp.netgridview
R.C
R.C

Reputation: 10565

GridView SortExpression issue

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.

Upvotes: 2

Views: 586

Answers (2)

R.C
R.C

Reputation: 10565

We need to use the GridView.EnablePersistedSelection Property. MSDN states that

If this property is false and a row is selected, the same row is selected when a new page is displayed even though the new page has different data in it. If you set this property to true, when you display a page that has different data in it, no row is selected. If you then return to the page on which a row was selected, that row is still selected.

Setting this property to true resolved my issue.

Upvotes: 3

Icarus
Icarus

Reputation: 63966

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;
        }

    }
}

Upvotes: 3

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