private void bindData(int startWeek, int endWeek, WebDataGrid web)
        {
            

            string strSQL = string.Empty;
            DataTable objTable = new DataTable();
  
            string userMaker=getUserMaker(startWeek, endWeek);
       }
    
            strSQL = "SELECT* FROM table ";
            objTable = new DataTable("Data");
            objTable = objAdoData.RetrieveData2Table(strSQL);

            web.ClearDataSource();
            web.ClearTemplates();

            if (objAdoData.Message.Length > 0)
            {
                return;
            }

            if (web.Columns.Count > 0)
            {
                web.Columns.Clear();
            }
            CreateWebDataGridColumns(web, objTable);
            web.DataSource = objTable;
            web.DataBind();
            
        }

  protected void CreateWebDataGridColumns(WebDataGrid wdg, DataTable dt)
        {
            wdg.ClearDataSource();
            wdg.ClearTemplates();
            wdg.Columns.Clear();

            BoundDataField BoundCol = new BoundDataField();
            BoundCol.Key = "Maker";
            BoundCol.Header.Text = "Maker";
            BoundCol.Width = 70;
            BoundCol.DataFieldName = "Maker";
            BoundCol.CssClass = "text-left";
            wdg.Columns.Add(BoundCol);

            for (int i = 1; i < dt.Columns.Count; i++)
            {
                TemplateDataField templateCol = new TemplateDataField();
                templateCol.Key = dt.Columns[i].ColumnName;
                templateCol.Header.Text = dt.Columns[i].ColumnName;
                templateCol.Width = 100;
                templateCol.ItemTemplate = new CustomItemTemplateByLink();
                templateCol.CssClass = "text-right";
                wdg.Columns.Add(templateCol);
            }

        }

I have four webdatagrid  that will bind with different week data. 

I use binddata() to pass week range and webdatagrid object.

And I have a dropdownlist that choose year value.

The default is current year. User can change ddl to see every year every week data.

Such as choose 2019 . He can see 

bindData(1, 13, wdgData1); 
bindData(14, 26, wdgData2);
bindData(27, 39, wdgData3);
bindData(40, 52, wdgData4);

_______________________________

WebDataGrid can display the right data at first time to enter the page.

But when I change the dropdownlist to see different year.

The data show null .

I make sure that the datatable has data that from database.

I don't know why  i had bind but they had not shown.

//this is ddl change method

protected void ddlYear_SelectedIndexChanged(object sender, EventArgs e)
{
string i = ddlYear.SelectedValue;
bindData(1, 13, wdgData1); 
bindData(14, 26, wdgData2);
bindData(27, 39, wdgData3);
bindData(40, 52, wdgData4);
}

// this is pageload method

protected void Page_Load(object sender, EventArgs e)
{

if (!Page.IsPostBack)
{
bindData(1, 13, wdgData1); 
bindData(14, 26, wdgData2);
bindData(27, 39, wdgData3);
bindData(40, 52, wdgData4);
}
}

You can see both of them is same calls.

This is first time enter. default 2019 year

When I change ddl to 2018 year , it empty

When I change back to 2019 , the original value can't show.

     <ig:WebDataGrid ID="wdgData1" runat="server" AutoGenerateColumns="false"
        StyleSetName="Default" StyleSetPath="../ig_res" Width="100%"
        >
        <Columns>
        </Columns>
        <Behaviors>
            <ig:Activation Enabled="true" />
            <ig:ColumnResizing Enabled="false" />
            <ig:ColumnFixing ShowLeftSeparator="true" ShowFixButtons="false" />
        </Behaviors>
    </ig:WebDataGrid>
    <br />

     <ig:WebDataGrid ID="wdgData2" runat="server" AutoGenerateColumns="false"
        StyleSetName="Default" StyleSetPath="../ig_res" Width="100%"
        >
        <Columns>
        </Columns>
        <Behaviors>
            <ig:Activation Enabled="true" />
            <ig:ColumnResizing Enabled="false" />
            <ig:ColumnFixing ShowLeftSeparator="true" ShowFixButtons="false" />
        </Behaviors>
    </ig:WebDataGrid>
    <br />
      <ig:WebDataGrid ID="wdgData3" runat="server" AutoGenerateColumns="false"
        StyleSetName="Default"   StyleSetPath="../ig_res" Width="100%"
        >
        <Columns>
        </Columns>
        <Behaviors>
            <ig:Activation Enabled="true" />
            <ig:ColumnResizing Enabled="false" />
            <ig:ColumnFixing ShowLeftSeparator="true" ShowFixButtons="false" />
        </Behaviors>
    </ig:WebDataGrid>
    <br />
    <ig:WebDataGrid ID="wdgData4" runat="server" AutoGenerateColumns="false"
        StyleSetName="Default" StyleSetPath="../ig_res" Width="100%"
        >
        <Columns>
        </Columns>
        <Behaviors>
            <ig:Activation Enabled="true" />
            <ig:ColumnResizing Enabled="false" />
            <ig:ColumnFixing ShowLeftSeparator="true" ShowFixButtons="false" />
        </Behaviors>
    </ig:WebDataGrid>

front end code