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[Solved] GridHyperLinkColumn Value dissappeared when RadGrid is rebind

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Grid

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illumination asked on 10 Sep 2009, 07:30 PM

I have a Radgrid that the first column is created with:

    
                    <telerik:RadGrid ID="RadGrid1" runat="server" AllowFilteringByColumn="True" Width="100%" 
        
                        AllowSorting="True" GridLines="None" Skin="Web20" OnNeedDataSource="RadGrid1_NeedDataSource" 
        
                         OnSortCommand="RadGrid1_SortCommand" OnItemCreated="RadGrid1_ItemCreated" AllowPaging="true"   
        
                         AutoGenerateColumns="False" > 
        
            <MasterTableView > 
        
            <Columns> 
        
                               <telerik:GridHyperLinkColumn DataNavigateUrlFields="EMPLOYEEID" DataNavigateUrlFormatString="~/Search.aspx?EMPLOYEEID={0}" 
        
                                    DataTextField="EMPLOYEEID" HeaderText="ID" AllowFiltering="true" FilterControlWidth="35px" UniqueName="EMPLOYEEID">  
        
                                    <HeaderStyle ForeColor="White" Font-Names="Arial Narrow" Font-Size="Small" />                  
        
                                    <ItemStyle Font-Names="Arial Narrow" Font-Size="Small" Font-Bold="True" Font-Underline="True" /> 
        
                                </telerik:GridHyperLinkColumn> 
        
                                <telerik:GridBoundColumn DataField="IDENTIFIER" HeaderText="IDENTIFIER" SortExpression="IDENTIFIER" 
        
                                    UniqueName="IDENTIFIER">  
        
                                </telerik:GridBoundColumn> 
        
            .....  
        
            </Columns> 
        
            <PagerStyle Mode="NumericPages" PageButtonCount="10" /> 
        
            </MasterTableView>

The problem I am having is:
Radgrid1 is generated on page load and it is working correctly... appeared with the first column with hyperlink ability. Then I click other grid control such as next page or filtering... then the ID dissappeared. so the first column only showing me dashes (-).
Can anybody help me on how to fix this problem?
Thank you.

3 Answers, 1 is accepted

answered on 12 Sep 2009, 08:04 AM

Hi illumination,

When you perform Search operation the Grid is populated in the button's click event. After that when you perform any operation that causes a PostBack the Grid will be empty since its DataSource is not set in the succeeding PostBacks.

So in order to retain the Search result while Paging/Sorting etc store the filtered result to a ViewState in the button click event and then in the NeedDataSource event populate the Grid again from the ViewState. NeedDataSource event will be fired each and every time a Grid operation is performed. Here is a Sample code:

ASPX:

    
               <telerik:RadGrid ID="RadGrid1" runat="server"  AllowPaging="true" PageSize="5"   ShowGroupPanel="true" OnNeedDataSource="RadGrid1_NeedDataSource"> 
        
                        <MasterTableView CommandItemDisplay="Top"> 
        
                        </MasterTableView> 
        
                        <ClientSettings AllowDragToGroup="true" AllowColumnsReorder="true" > 
        
                        </ClientSettings> 
        
                    </telerik:RadGrid> 
        
              <asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Filter" />

CS:

    
              protected void RadGrid1_NeedDataSource(object source, GridNeedDataSourceEventArgs e) 
        
                { 
        
                    if (ViewState["GridData"] != null) 
        
                    { 
        
                        RadGrid1.DataSource = ViewState["GridData"]; 
        
                    } 
        
                } 
        
                protected void Button1_Click(object sender, EventArgs e) 
        
                { 
        
                     string connectionstring = "Data Source=MyData; Initial Catalog=NorthWind;User ID=***; Password=*****"; 
        
                     SqlConnection conn = new SqlConnection(connectionstring); 
        
                     SqlCommand cmd = new SqlCommand(); 
        
                         conn.Open(); 
        
                        SqlDataAdapter adp = new SqlDataAdapter("select * from  Products", conn); 
        
                        DataTable dt = new DataTable(); 
        
                        adp.Fill(dt); 
        
                        ViewState["GridData"] = dt; 
        
                        if (ViewState["GridData"] != null) 
        
                        { 
        
                            RadGrid1.DataSource = ViewState["GridData"]; 
        
                        } 
        
                        RadGrid1.DataBind(); 
        
                        conn.Close();  
        
                }

Thanks
Princy