When binding to a TreeGridModel, I'm receiving a NullReferenceException. Object reference not set to an instance of object exception. 

In my view I'm binding to a TreeGridModel..

@model XNamespace.Models.XModel

<div>@(Html.Infragistics().TreeGrid(Model.XTreeGridModel)) </div>

XTreeGridModel is basiscally a property in my XModel class to return a TreeGridModel.

In my XModel class, I'm constructing TreeGridModel

// Create
m_treeGridModel = new TreeGridModel();

// Set properties
m_treeGridModel.ID = "treeGridModel";
m_treeGridModel.AutoGenerateColumns = false;
m_treeGridModel.AutoGenerateLayouts = false;
//m_treeGridModel.PrimaryKey = ColumnIndex.StrategyInstId.ToString();
//m_treeGridModel.ForeignKey = ColumnIndex.PID.ToString();
m_treeGridModel.PrimaryKey = "ID";
m_treeGridModel.ForeignKey = "PID";
m_treeGridModel.LoadOnDemand = false;
m_treeGridModel.InitialExpandDepth = 1;
m_treeGridModel.Columns = new List<GridColumn>();
m_treeGridModel.Columns.Add(new GridColumn() { HeaderText = "ID", Key = "ID", DataType = "number", Width = "0%", Hidden = true });
m_treeGridModel.Columns.Add(new GridColumn() { HeaderText = "PID", Key = "PID", DataType = "number", Width = "0%", Hidden = true });
m_treeGridModel.Columns.Add(new GridColumn() { HeaderText = "Name", Key = "Name", DataType = "string", Width = "10%" });
m_treeGridModel.Columns.Add(new GridColumn() { HeaderText = "Date Modified", Key = "DateModified", DataType = "string", Width = "10%" });
m_treeGridModel.Columns.Add(new GridColumn() { HeaderText = "Type", Key = "Type", DataType = "string", Width = "10%" });
m_treeGridModel.Columns.Add(new GridColumn() { HeaderText = "Size", Key = "Size", DataType = "string", Width = "10%" });

XData q1 = new XData();  // XData is a class with ID, PID, Name, DateModified, Type and Size members
q1.ID = 1;
q1.PID = -1;
q1.Name = "XName";
q1.DateModified = "XDM";
q1.Type = "XType";
q1.Size = "323";

m_xDataList.Add(q1);

XData q2 = new XData();
q2.ID = 2;
q2.PID = -1;
q2.Name = "XName";
q2.DateModified = "XDM";
q2.Type = "XType";
q2.Size = "323";

m_xDataList.Add(q2);

m_treeGridModel.DataSource = m_quoteDataList.AsQueryable();

If I comment out the binding statement, I'm able to see the empty TreeGrid. But, when I uncomment the above statement, I get a null reference exception.