[JSGrid] Error in jsgrid.debug.js

Hello,

I am working on a JSgrid dev for SharePoint & Project Server 2010. When I switch from a hierarchical view to a normal view, I get the following error from jsgrid.debug.js:

Microsoft.JScript runtime error: 'columns.GetColumnByKey(...)' is null or not an object.

Here's the client code :

GridManager = function () {

	// Public vars (reachable during execution).
	this.JSGridControl = null; 	// Variables for the JSGrid control instance and the grid properties
	this.Properties = null; 	// Variables for the JSGrid control instance and the grid properties
	this.JSGridControlInitializer = null;

	// Private vars (unreachable during execution).
	var _jsGridParams; 		// Variable for the JSGrid params
	var _dataSource; 		// Variable for the grid data source
	var _tableCache; 		// Variable for the grid data source cache
	var _projectStatusID; // Variable for the project status
	var _orderByColumnName; // Variables for sorting.
	var _isDescending; 		// Variables for sorting.

	// Define Filter/Grouping/Detailed view vars + set default values.
	this.DetailedView = false;
	this.Grouping = false;
	this.CurrentFilterId = null;
	this.GroupingField = null;
	this.Grouping = false;

	this.DataSource = function () {
		return _dataSource;
	};

	this.Init = function (jsGridControl, initialData, props) {
		this.JSGridControl = jsGridControl;
		this.JSGridControlInitializer = jsGridControl;
		this.Properties = props;

		// Set default view.
		this.DetailedView = props.detailedView;
		this.Grouping = props.grouping;
		this.GroupingField = props.groupingField;
		this.CurrentFilterId = props.defaultFilterId;

		// get the initial data.
		var args = Sys.Serialization.JavaScriptSerializer.serialize({
			Command: commands.GetData,
			DetailedView: GM.DetailedView,
			Grouping: GM.Grouping,
			GroupingField: GM.GroupingField,
			FilterId: GM.CurrentFilterId
		});

		// Client calls the display callback.
		eval(callbacks.displayCallback);
	}
	
	// ...
	
	this.Callback_GetData = function (data) {

		GM.HideLoadingDiv();

		// Show data in the grid.
		if (data != null && data != '') {
			// First deserialisation.
			var responseData = Sys.Serialization.JavaScriptSerializer.deserialize(data);

			if (responseData.ErrorMessage != null && responseData.ErrorMessage != '') {
				// Error occured.
				alert(responseData.ErrorMessage);
			} else {

				// Deserialise once more to get the JsonGrid object.
				_gridData = SP.JsGrid.Deserializer.DeserializeFromJson(responseData.JsonGrid);
				if (!_dataSource)
					_dataSource = new SP.JsGrid.StaticDataSource(_gridData);
				else
					_dataSource.LoadSerializedData(_gridData);
				_jsGridParams = _dataSource.InitJsGridParams();


				// Sets the table cache in the _tableCache variable.
				_tableCache = _jsGridParams.tableCache;

				// OLD VERSION
				if (!GM.JSGridControl.IsInitialized())
					GM.JSGridControl.Init(_jsGridParams);
				else
					GM.JSGridControl.SetTableView(_jsGridParams.tableViewParams);

				GM.JSGridControl.SetSplitterPosition(435);
				GM.JSGridControl.DisableEditing();
			}
		}
	}
	
	// ...
}

		public string GetCallbackResult()
		{
			CallbackResult cbr = new CallbackResult();
			try
			{
				switch (_callbackArgs.Command)
				{
					case Commands.GetData:
						cbr = GetData();
						break;

					default:
						throw new NotImplementedException();
				}
			}
			catch (Exception ex)
			{
				cbr.ErrorMessage = ex.ToString();
			}
			return Utils.Jsonify(cbr);
		}
...
		private CallbackResult GetData()
		{
			DateTime start = DateTime.Now;
			CallbackResult cbr = new CallbackResult();
			try
			{
				// Set vars.
				this.DetailedView = _callbackArgs.DetailedView;
				this.Grouping = _callbackArgs.Grouping;

				Modes displayMode = this.GetMode(_callbackArgs.DetailedView, _callbackArgs.Grouping);

				// get selected filter ...
				Filter selectedFilter = null;
				if (!string.IsNullOrEmpty(_callbackArgs.FilterId))
				{
					selectedFilter = this.GetSelectedFilter(new Guid(_callbackArgs.FilterId));
				}

				// Retrieve the JSGridDisplay corresponding to the current mode.
				JSGridDisplay currentJSGridDisplay = GetJSGridDisplay(displayMode);
				List<GridColumn> gridColumns = GetGridColumns(currentJSGridDisplay);

				// Build flat data
				DataTable data = this.BuildGanttData(currentJSGridDisplay, selectedFilter, this.DetailedView, this.Grouping, _callbackArgs.GroupingField);

				// Create a grid serializer to connect to data
				GridSerializer gds = new GridSerializer(
					SerializeMode.Full,
					data,
					this.KeyColumn,
					new FieldOrderCollection(new String[] { Columns.ProjectName }),
					GetGridFields(data),
					//GridUtilities.GetGridColumns(this.DetailedView, this.Grouping)
					gridColumns // GetGridColumns(displayMode)
				);

				// Enable hierarchy
				if (this.DetailedView || this.Grouping)
				{
					gds.EnableHierarchy(null, Columns.TaskParentUID, Columns.ProjectName, false);
					gds.SetHierarchyStateExpandedToLevel(0);
				}

				// Get earliest and latest dates of data
				var query = from row in data.AsEnumerable()
							select row.Field<DateTime?>(Columns.ProjectStartDate);

				DateTime? earliestDate = (query.Count() > 0) ? query.Min<DateTime?>() : DateTime.Now.AddDays(-30);
				DateTime? latestDate = (query.Count() > 0) ? query.Max<DateTime?>() : DateTime.Now.AddDays(30);

				// Enable Gantt chart.
				gds.EnableGantt(earliestDate.Value, latestDate.Value, GanttUtilities.StyleInfo, Columns.ProjectStartDate);

				// set the JsonGrid property.
				cbr.JsonGrid = gds.ToJson(new Serializer());
			}
			catch (Exception ex)
			{
				cbr.ErrorMessage = ex.ToString();
			}

			TimeSpan span = DateTime.Now.Subtract(start);
			if (DebugMode) TraceProvider.LogFormattedPerf("BasicInfo.GetData() took [{0}]ms. (including SQL exec time).", span.ToString());
			return cbr;
		}

I hope someone can help me out on this!

Have a nice day