Must declare the scalar variable in gridview C# asp.net -

        <asp:gridview id="gridview1" runat="server" datasourceid="sqldatasource1" autogeneratecolumns="false" onselectedindexchanged="gridview1_selectedindexchanged" onrowcommand="gridview1_rowcommand">             <columns>                 <asp:templatefield headertext="id">                     <itemtemplate>                         <asp:label id="lblid" runat="server" text='<%#bind("id") %>'></asp:label>                     </itemtemplate>                 </asp:templatefield>                 <asp:templatefield headertext="client name">                     <itemtemplate>                         <asp:label id="lblname" runat="server" text='<%#bind("client_name") %>'></asp:label>                     </itemtemplate>                 </asp:templatefield>                 <asp:templatefield headertext="email">                     <itemtemplate>                         <asp:label id="lblemail" runat="server" text='<%#bind("email") %>'></asp:label>                     </itemtemplate>                 </asp:templatefield>                 <asp:templatefield headertext="google email">                     <itemtemplate>                         <asp:label id="lblgemail" runat="server" text='<%#bind("google_email") %>'></asp:label>                     </itemtemplate>                 </asp:templatefield>                 <asp:templatefield headertext="contact number">                     <itemtemplate>                         <asp:label id="lblcont" runat="server" text='<%#bind("contact_number") %>'></asp:label>                     </itemtemplate>                 </asp:templatefield>                  <asp:templatefield headertext="add">                      <itemtemplate>                          <asp:button id="btnadd" runat="server" text="add" onclick="btnadd_click" />                     </itemtemplate>                 </asp:templatefield>                 <asp:templatefield headertext="delete">                      <itemtemplate>                        <asp:button id="btndelete" runat="server" commandname="delete" onclick="btndelete_click" text="delete" />                     </itemtemplate>                 </asp:templatefield>              </columns>         </asp:gridview>               <asp:sqldatasource id="sqldatasource1" runat="server" connectionstring="<%$ connectionstrings:logistics %>"                   selectcommand="select * clientrequest"                   deletecommand="delete clientrequest client_name = @client_name">      <deleteparameters>         <asp:parameter name="client_name" type="string" />     </deleteparameters> </asp:sqldatasource> 

i getting error of must declare scaler variable on delete command @client_name column in table , bind client_name label on aspx page

delete button used under template field

the error comes sql try execute

delete clientrequest client_name = @client_name   

you need provide @client_name parameter query, work.