I'm doing some tests on WebDataGrid in ASP.Net 4.0, and I have this error:

[InvalidOperationException: DataKeyField is invalid] Infragistics.Web.UI.Framework.Data.DataSourceAdapter.Select(DataSourceSelectArguments arguments) +651 Infragistics.Web.UI.Framework.Data.DataSourceObjectView.ExecuteSelect(DataSourceSelectArguments arguments) +73 System.Web.UI.DataSourceView.Select(DataSourceSelectArguments arguments, DataSourceViewSelectCallback callback) +21 System.Web.UI.WebControls.DataBoundControl.PerformSelect() +143 System.Web.UI.WebControls.BaseDataBoundControl.DataBind() +74 Infragistics.Web.UI.GridControls.WebDataGrid.DataBind() +974 Infragistics.Web.UI.Framework.Data.FlatDataBoundControl.EnsureDataBound() +73 Infragistics.Web.UI.GridControls.WebDataGrid.EnsureDataBound() +186 Infragistics.Web.UI.GridControls.WebDataGrid.CreateChildControls() +75 System.Web.UI.Control.EnsureChildControls() +102 Infragistics.Web.UI.GridControls.WebDataGrid.EnsureChildControls() +129 System.Web.UI.Control.PreRenderRecursiveInternal() +42 System.Web.UI.Control.PreRenderRecursiveInternal() +175 System.Web.UI.Control.PreRenderRecursiveInternal() +175 System.Web.UI.Control.PreRenderRecursiveInternal() +175 System.Web.UI.Control.PreRenderRecursiveInternal() +175 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2496

My WebDataGrid in .aspx page is defined in this way:

<ig:WebDataGrid runat="server" ID="grdOrders" Height="400px" Width="600px" EnableViewState="true">

<Behaviors>

<ig:Sorting Enabled="true"></ig:Sorting>

<ig:Filtering Enabled="true"></ig:Filtering>

<ig:ColumnMoving Enabled="true"></ig:ColumnMoving>

<ig:EditingCore Enabled="true">

<Behaviors>

<ig:CellEditing Enabled="true"></ig:CellEditing>

</Behaviors>

</ig:EditingCore>

</Behaviors>

</ig:WebDataGrid>

 

While in the code behind I have only this code:

Dim dtOrders As DataTable

Dim sSql As String = "SELECT OrderYear,OrderType,OrderNumber,CustomerCode FROM Orders WHERE OrderYear=2012"

LoadTable(DBConnection, dtOrders, "Ordini", sSql, True, New String() {"OrderYear", "OrderType", "OrderNumber"})

grdOrders.DataSource = dtOrders

grdOrders.DataKeyFields = "OrderYear,OrderType,OrderNumber"

LoadTable is a function which executes the SQL script, loads data into the DataTable dtOrders and sets the Primary Key with the fields "OrderYear", "OrderType", and "OrderNumber"

The problem is that if I comment the "grdOrders.DataKeyFields..." row, everything works well, but I'm not able to modify any cell in the html page (if I try to do that, at first postback an error saying that I must set DataKeyField is triggered). Instead, if I uncomment that line, the page doesn't show up and the "DataKeyField is invalid" error is triggered.

How can I solve this? Thanks for any help!