title: how to check only one checkbox in gridview
body: <p>i am using a gridview and my problem is that a user can select only one checkbox in the grid if the user select second checkbox previous will we unchecked . i try javascript but that not works for me can you please help me how can i do this . Below is my gridview </p>
  
  <pre><code>    &lt;data:EntityGridView ID="gvService" Width="100%"  DataKeyNames="PriceSystemID" runat="server"
                                              OnRowEditing="GridView1_RowEditing" OnRowCommand="gvServices_ItemCommand" AutoGenerateColumns="False"
                                              OnRowDeleting="gvService_RowDeleting" ShowFooter="true" OnRowCancelingEdit="gvService_RowCancelingEdit" 
                                              &gt;
                                              &lt;Columns&gt;
                                                  &lt;asp:TemplateField HeaderText="Service"&gt;
                                                      &lt;ItemTemplate&gt;
                                                          &lt;data:EntityDropDownList runat="server" ID="dataServiceTypeId1"  DataSourceID="ServiceTypeIdServiceTypesDataSource"
                                                              DataTextField="Description" DataValueField="ServiceTypeId" SelectedValue='&lt;%# Bind("ServiceTypeID") %&gt;' Width="200px"
                                                              AppendNullItem="true" Required="true" NullItemText="&lt; Please Choose ...&gt;" ErrorText="Required" /&gt;
                                                          &lt;data:ServiceTypesDataSource ID="ServiceTypeIdServiceTypesDataSource" runat="server"
                                                              SelectMethod="GetAll" /&gt;
                                                      &lt;/ItemTemplate&gt;
                                                      &lt;EditItemTemplate&gt;
                                                          &lt;data:EntityDropDownList runat="server" ID="dataServiceTypeId2" DataSourceID="ServiceTypeIdServiceTypesDataSource"
                                                               DataTextField="Description" DataValueField="ServiceTypeId" Width="200px" AutoPostBack="true"
                                                              SelectedValue='&lt;%# Bind("ServiceTypeID") %&gt;' AppendNullItem="true" Required="true"
                                                              NullItemText="&lt; Please Choose ...&gt;" ErrorText="Required" /&gt;
                                                          &lt;data:ServiceTypesDataSource ID="ServiceTypeIdServiceTypesDataSource" runat="server"
                                                              SelectMethod="GetAll" /&gt;
                                                      &lt;/EditItemTemplate&gt;
                                                      &lt;FooterTemplate&gt;
                                                        &lt;data:EntityDropDownList runat="server" ID="dataServiceTypeId3" DataSourceID="ServiceTypeIdServiceTypesDataSource"
                                                              AutoPostBack="true" DataTextField="Description" DataValueField="ServiceTypeId" Width="200px"
                                                              SelectedValue='&lt;%# Bind("ServiceTypeID") %&gt;' AppendNullItem="true" Required="true"
                                                              NullItemText="&lt; Please Choose ...&gt;" ErrorText="Required" /&gt;
                                                          &lt;data:ServiceTypesDataSource ID="ServiceTypeIdServiceTypesDataSource" runat="server"
                                                              SelectMethod="GetAll" /&gt;
                                                      &lt;/FooterTemplate&gt;
                                                  &lt;/asp:TemplateField&gt;
                                                  &lt;asp:TemplateField HeaderText="Default"&gt;
                                                      &lt;ItemTemplate&gt;
                                                          &lt;asp:CheckBox ID="chkDefault" Checked='&lt;%# Bind("IsDefault") %&gt;'   
                                                              runat="server" /&gt;
                                                      &lt;/ItemTemplate&gt;
                                                      &lt;EditItemTemplate&gt;
                                                          &lt;asp:CheckBox ID="chkDefault" Checked='&lt;%# Bind("IsDefault") %&gt;' runat="server"   /&gt;
                                                      &lt;/EditItemTemplate&gt;
                                                      &lt;FooterTemplate&gt;
                                                        &lt;asp:CheckBox ID="chkDefault" Checked='&lt;%# Bind("IsDefault") %&gt;' runat="server"   /&gt;
  
                                                      &lt;/FooterTemplate&gt;
                                                  &lt;/asp:TemplateField&gt;
  </code></pre>
  
  <p>
                                                          
                                                              
                                                              ' CausesValidation="false">
                                                          
                                                          
                                                              
                                                                
                                                          
                                                          
                                                           
                                                            
                                                          
                                                      </p>
  
  <pre><code>  &lt;EmptyDataTemplate&gt;
   &lt;/EmptyDataTemplate&gt;
  
      &lt;/data:EntityGridView&gt;
  </code></pre>