Show data from another table when select a row in gridview

Question

User-340993414 posted

Hello,

I have the following diagram :

I want to show Contact (if exists) when selecting a row in servers.

Here is my aspx code that show a list of servers :

<asp:GridView ID="serversGV" runat="server"
AutoGenerateColumns="False"
DataKeyNames="id,service_id"
DataSourceID="serversDS" AllowPaging="True"
>
<Columns>
<asp:CommandField ShowSelectButton="True" />
<asp:BoundField DataField="id" HeaderText="id" ReadOnly="True" SortExpression="id" />
<asp:BoundField DataField="name" HeaderText="name" SortExpression="name" />
<asp:BoundField DataField="service_id" HeaderText="service_id" SortExpression="service_id" />
<asp:BoundField DataField="entite_id" HeaderText="entite_id" SortExpression="entite_id" />
</Columns>
</asp:GridView>
<asp:EntityDataSource ID="serversDS" runat="server"
ConnectionString="name=InventoryEntities"
DefaultContainerName="InventoryEntities"
EnableFlattening="False" EntitySetName="Servers"
>
</asp:EntityDataSource>

Note that I use two keys in DataKeyNames to retrieve the service_id key.

Here is my aspx code for EntityDataSource for Contacts :

<asp:EntityDataSource ID="tagserviceEDS" runat="server" 
        ConnectionString="name=InventoryEntities" 
        DefaultContainerName="InventoryEntities" 
        EnableFlattening="False" 
        EntitySetName="Tag_Services"
        Include="Contact_Service.Contacts"
        AutoGenerateWhereClause="true"        
        OnSelected="tagserviceEDS_Selected">
        <WhereParameters>
            <asp:ControlParameter ControlID="serversGV" Name="id" PropertyName="SelectedDataKey.Values[service_id]" DbType="Int32" />
        </WhereParameters>
    </asp:EntityDataSource>

I also insert a GridView :

<asp:GridView ID="gv" runat="server" DataSourceID="tagserviceEDS">
        <Columns>
            <asp:BoundField DataField="Contacts.firstName" HeaderText="firstName" ReadOnly="true" />
        </Columns>
    </asp:GridView>

With code behind :

protected void tagserviceEDS_Selected(object sender, EntityDataSourceSelectedEventArgs e)
        {
            if (e.Results != null)
            {
                var tagservice = e.Results.Cast<DAL.Tag_Services>();
                var res = tagservice.First().Contact_Service;

                if (res.Count > 0)
                {
                    gv.DataSource = res.ToList();
                    gv.DataBind();
                }
            }
        }

Like that I receive an error that say something like the data in the second gridview cannot be modified during bind. (I'm french so I don't have the exact error in english).

If I remove the DataSourceID in gridview gv, the event Select is not raised.

What am I doing wrong?  How can I show contacts?

Thanks for your help.

Answer 1

User-893317190 posted

Hi miniil02,

It seems you want to change the datasource of your gridview gv when it has bound data of type  tag_services. It will cause error.
I suggest that you could use gridview ‘s  OnSelectedIndexChanged event to help bind data of type contacts when the select index of gridview  changes.

Below is my code.

<asp:gridview runat="server" ID="gridview" AutoGenerateColumns="False" DataKeyNames="Id" DataSourceID="EntityDataSource1" OnSelectedIndexChanged="gridview_SelectedIndexChanged" 
                SelectedIndex="1"  autogenerateselectbutton="True" >
                <Columns>
        
                    <asp:BoundField DataField="Id" HeaderText="Id" ReadOnly="True" SortExpression="Id" />
                    <asp:BoundField DataField="name" HeaderText="name" SortExpression="name" />
                    <asp:BoundField DataField="Tag_servicesId" HeaderText="Tag_servicesId" SortExpression="Tag_servicesId" />
                </Columns>
                <selectedrowstyle backcolor="LightCyan"
         forecolor="DarkBlue"
         font-bold="true"/>  

            </asp:gridview>
            <asp:EntityDataSource ID="EntityDataSource1" runat="server" ConnectionString="name=Model1Container" DefaultContainerName="Model1Container" EnableFlattening="False" EntitySetName="Servers">
            </asp:EntityDataSource>
        </div>



        <asp:GridView ID="gv" runat="server"  AutoGenerateColumns="False" >
        <Columns>
       
           <asp:BoundField DataField="firstName" HeaderText="firstName" ReadOnly="true" />
        </Columns>
    </asp:GridView>

Code behind.

//the dbcontext object
Model1Container container = new Model1Container();
        protected void Page_Load(object sender, EventArgs e)
        {
            Servers server = container.Servers.Find(1);
            List<Contacts> contacts = server.Tag_services1.Contact_Service.Select(cs => cs.Contact).ToList();
            gv.DataSource = contacts;
            gv.DataBind();
        }

protected void gridview_SelectedIndexChanged(object sender,EventArgs e)
        {
            
           //get the id of selected server
            int b = (int)gridview.SelectedDataKey.Value;
          Servers server=  container.Servers.Find(b);

            // use linq to find all the contacts related to the selected server
           List<Contacts> contacts = server.Tag_services1.Contact_Service.Select(cs=>cs.Contact).ToList();
            gv.DataSource = contacts;
            gv.DataBind();
            
        }

And the result.

Best regards ,

Ackerly Xu