Gridview Sorting using attribute [Source Code]

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Introduction

Many developers who try to sort a GridView generally use the ViewState for maintaining the last position of the GridView. Here, I want to show you a new technique of doing this...

Here is my GridView code:

<asp:GridView ID="GridView1" 
runat="server" AllowSorting="true" 
        AutoGenerateColumns="False" onsorting="GridView1_Sorting" 
        CurrentSortField="employeeid" CurrentSortDirection="ASC" 
        onrowcreated="GridView1_RowCreated" AllowPaging="true" 
        CaptionAlign="Bottom" onpageindexchanging="GridView1_PageIndexChanging" 
        onprerender="GridView1_PreRender" 
         PageSize="2">
      <Columns>
        <asp:BoundField  DataField="EmployeeId" HeaderText="Last Name"  
              ItemStyle-Width="15%" SortExpression="EmployeeId" >
        <ItemStyle Width="15%"></ItemStyle>
          </asp:BoundField>
        <asp:BoundField DataField="Name" 
        HeaderText="First Name"  ItemStyle-Width="15%" 
              SortExpression="Name"  >
             <ItemStyle Width="15%"></ItemStyle>
          </asp:BoundField>
        <asp:BoundField DataField="gender" 
        HeaderText="Email" ItemStyle-Width="15%" >
            <ItemStyle Width="15%"></ItemStyle>
          </asp:BoundField>
        <asp:TemplateField HeaderText="Change Password"  
        ItemStyle-Width="15%">

        <ItemTemplate>

            <asp:LinkButton ID="imgbtn1" 
            runat="server">change password</asp:LinkButton>
        </ItemTemplate>

             <ItemStyle Width="15%"></ItemStyle>
          </asp:TemplateField>
        <asp:BoundField DataField="city" 
        HeaderText="Date created"  ItemStyle-Width="15%">
             <ItemStyle Width="15%"></ItemStyle>
          </asp:BoundField>
        </Columns>
        <PagerSettings Mode="NextPreviousFirstLast" />
    </asp:GridView>

And I sort using the attribute property of the GridView.

See here, through attribute, I am maintaining last sorted record. Suppose last I sort asc then asc and if I last sorted desc then desc. This is how it works:

private void GridView1_Sorting (GridView gridview, GridViewSortEventArgs e, 
         out SortDirection sortDirection, out string sortField)
{
    sortField = e.SortExpression;
    sortDirection = e.SortDirection;
    if (gridview.Attributes["CurrentSortField"] != null && 
         gridview.Attributes["CurrentSortDirection"] != null)
    {
        if (sortField == gridview.Attributes["CurrentSortField"])
        {
            if (gridview.Attributes["CurrentSortDirection"] == "ASC")
            {
                sortDirection = SortDirection.Descending;
            }
            else
            {
                sortDirection = SortDirection.Ascending;
            }
        }
        gridview.Attributes["CurrentSortField"] = sortField;
        gridview.Attributes["CurrentSortDirection"] = 
           (sortDirection == SortDirection.Ascending ? "ASC" : "DESC");
    }
}

Now you will get the last sorted and filed easily and it generally shows that while developing, there is too much load on the page using the viewstate.

Code Description

In sorting, you have two options asc/desc.

Now, if you are sorting by asc, then in gridview attribute add to CurrentSortDirection= asc.

When user clicks for the second time, we get value from CurrentSortDirection asc so now do desc and add CurrentSortDirection =desc.

Simple, but very useful.

I am sure this will definitely help you. If you still did not get it, take a look at the source code.