Lookup field generating error

[vaioklm]

I create a lookup field using the following code:

Dim luSysNo As GridFX.WebForms.LookupFieldluSysNo = New GridFX.WebForms.LookupFieldluSysNo.DataPath = "cll_sys_no"luSysNo.ReadOnly = FalseluSysNo.MissingValueText = "Missing"Dim liItem As New GridFX.WebForms.LookupItemliItem.Text = "Test"liItem.Value = "0"luSysNo.LookupItems.Add(liItem)DataFields.Add(CType(luSysNo, GridFX.WebForms.DataField))Dim fcSysNo As GridFX.WebForms.FieldColumnfcSysNo = New GridFX.WebForms.FieldColumn(CType(luSysNo, GridFX.WebForms.DataField))fcSysNo.Title = ""fcSysNo.Visible = TruefcSysNo.Style.Wrap = FalseColumns.Add(fcSysNo)

 The grid renders fine and I see my "Test" and "Missing" values as I would expect.  But as soon as I put it into edit mode, I get the following error:

There was a problem while processing your request.  The specific error message was: Exception type: System.NullReferenceExceptionMessage: Object reference not set to an instance of an object.Stack Trace:   at GridFX.WebForms.LookupField.n() at GridFX.WebForms.LookupField.p() at GridFX.WebForms.LookupField.q() at GridFX.WebForms.LookupField.a(ListItemCollection A_0, LookupFieldInputSettings A_1) at GridFX.WebForms.LookupField.a(IFieldControl A_0, Object A_1) at GridFX.WebForms.DataField.i(IFieldControl A_0) at dc.b() at l3.k() at System.Web.UI.Control.EnsureChildControls() at l3.c(EventArgs A_0) at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Control.AddedControl(Control control, Int32 index) at System.Web.UI.ControlCollection.AddAt(Int32 index, Control child) at GridFX.WebForms.OutputCellContainer.b.a(Int32 A_0, OutputCell A_1) at GridFX.WebForms.OutputCellContainer.a(Object A_0, ListChangeEventArgs`1 A_1) at GridFX.WebForms.GridItem.a(Object A_0, ListChangeEventArgs`1 A_1) at GridFX.WebForms.ObservableList`1.a(ListChangeEventArgs`1 A_0) at GridFX.WebForms.ObservableList`1.Add(T item) at is.d() at GridFX.WebForms.GridItem.t() at GridFX.WebForms.GridItem.set_Editing(Boolean value) at GridFX.WebForms.GridCommands.g(CellContainerCommandArgs`1 A_0) at GridFX.WebForms.Command`1.b(TArgs A_0) at GridFX.WebForms.Command`1.a(CommandArgs A_0) at GridFX.WebForms.Grid.a(String A_0, pb A_1) at GridFX.WebForms.Grid.i(String A_0)

 If I remove the lookup field, the grid will go into edit mode without error.

[AngelR]

What event are you using when creating the Lookup Field?

[vaioklm]

The DataBinding Event.  That is where I am adding all of my columns to the Grid.

[AngelR]

Hi, sorry about the delay in getting a response.  The exception you got could be a limitation in Grid.Databinding event. We add a new event (Grid.DataSourceSelecting) that will be available in the next Service Pack, to be available soon.

This new event (DataSourceSelecting) overcomes some limitations we were having in the Grid_Databind event, most of them when connecting the grid programmatically. From now on when you use Grid FX Smart Tag Wizard to choose a datasource to connect the grid you'll see a new option: In Code and once you select it, an Event Handler will be created and a grid property will be set to true: DataSourceInCode.

To try this, there is a recent Hotfix that you can download to test. You will receive a personalized message with download instructions.

Here is a sample using BrokerageCompany and Agents tables I used to populate a Lookup field dynamically in the Grid.DataSourceSelecting Event.

Protected Sub Grid1_DataSourceSelecting(ByVal sender As Object, ByVal e As GridFX.WebForms.DataSourceSelectingEventArgs) Handles Grid1.DataSourceSelecting

 

'Let's populate the grid using Agents Datasource

Grid1.DataSource = Data_BusinessObject.GetAgents()

'Let's fill a different datasource with Brokerage CompaniesDim BrokersDv As New System.Data.DataView

BrokersDv = Data_BusinessObject.GetBrokers()

 

'Casting the brokerage_id field as the LookupField to be filledDim LookupField As New GridFX.WebForms.LookupField

LookupField = Grid1.DataFields(

"brokerage_id")

'for every datarow in Brokerage_Company table we add an Item to brokerage_id LookupField

'Brokerage_name will be looked up to replace brokerage_id valueFor Each row As Data.DataRow In BrokersDv.Table.Rows

Dim LookupFieldItem As New GridFX.WebForms.LookupItemLookupFieldItem.Text = row.Item("brokerage_name")LookupFieldItem.Value = row.Item("brokerage_id")

LookupField.LookupItems.Add(LookupFieldItem)

Next

End Sub

Let me know if this helps.