How to create Nested Data list, data grid or data repeater simple

Dear All,
The simplest way of create nested datalist with parent child table relation is given below:

 protected void loadData()
        {
           //Note: For Define your connection string i am not writing it because it is in my web.config and i load it through my internal class

             DataSet ds = new DataSet();
          // my private class that contains sql execute funtions, I pass the SQL parameters and Values through array
            UDF myudf = new UDF();
            string spName = "bvs_payInvoice";
         
            string[] field = new string[5];
            string[] fieldValue = new string[field.Length];

            field[0] = "@startDate";
            field[1] = "@endDate";
            field[2] = "@searchType";
            field[3] = "@keyWord";
            field[4] = "@status";
             
            fieldValue[0] = startDate;
            fieldValue[1] = endDate;
            fieldValue[2] = searchType;
            fieldValue[3] = keyword;
            fieldValue[4] = status;
               
            // this is my own function that execute the data set through passing array parameters
            ds = myudf.loadDataSet(spName, field, fieldValue);
         
           // this is an actual trick
           // Load two table in one ds (see my next post)

           // define Parent column in which you need to create the relation
            DataColumn parentColumn1 = ds.Tables[0].Columns[1];

           // Define Child column in which you need to create the relation 
            DataColumn childColumn1 = ds.Tables[1].Columns[1];

           // Define relation, the "detailDataset" is the name of your virtual table that you can use in your front end code.. or aspx page
            DataRelation dr = new DataRelation("detailDataset", parentColumn1, childColumn1, false);

           // Add relation with your ds  
            ds.Relations.Add(dr);
         
           // Assigning Data source and binding.
             DataList1.DataSource = ds;
            DataList1.DataBind();


******************
Front End
******************



                         // Call your main parent dataset fields
       <asp:DataList ID="DataList1"  >
<ItemTemplate><%# DataBinder.Eval(Container.DataItem, "Your column Name")%>

                        // Create nested datalist 
     <asp:DataList ID="DataList2" runat="server"  datasource='<%# DataBinder.Eval(Container, "DataItem.detailDataset") %>'>
                 // Call your main Child dataset fields 
                   <ItemTemplate>   <%# DataBinder.Eval(Container.DataItem, "Your column Name")%></ItemTemplate>
   
</asp:DataList>
               </ItemTemplate>                        
                   

</asp:DataList>

******************
How you access the nested DataList items
******************

first you need to initialize the controller
 DropDownList ddlhrs= default (DropDownList);
HiddenField parentRefId = default (HiddenField);
same like above you need to initialize your all controllers

//PreviewForm is your datalist name
  for (int i = 0; i <= previewForm.Items.Count - 1; i++)
{
   ddlhrs = (DropDownList)previewForm.Items[i].FindControl("DropDownList1");

   // access your control
  ddlhrs.SelectedValue.ToString();

   //assigned  nested datalist to control
    dl1 = (DataList)previewForm.Items[i].FindControl("DataList2");
    for (int j = 0; j <= dl1.Items.Count - 1; j++)
                 {
                   //Assign the Refrence in child datalist controller
                    parentRefId = (HiddenField)dl1.Items[j].FindControl("parentRefId");
                    parentRefId.Value.ToString();
                }

}








You can use the same technique with Data table, data list, and repeater or data table + repeater or data table + data list or data list + data table in short you create any sort of combination

I hope this post helps you allot

Regards
Rashid Imran Bilgrami
CEO
Best visualization
http://www.bestvisualization.com