Export to Excel from Datasource control not working

Object cannot be cast from DBNull to other types.

My code looks like the code I will paste below. I have attached my code in full.

Thanks very much,

Alex Jermy

DataTable dt = new DataTable("PlanningUnit");

protected void Page_Load(object sender, EventArgs e)

this.PlanningUnitsGrid.Model.Columns[2].Tooltip = "Code";

this.PlanningUnitsGrid.Model.Columns[3].Tooltip = "Job";

this.PlanningUnitsGrid.Model.Columns[4].Tooltip = "Name";

this.PlanningUnitsGrid.Model.Columns[5].Tooltip = "Billing";

this.PlanningUnitsGrid.Model.Columns[6].Tooltip = "Sales Budget";

this.PlanningUnitsGrid.Model.Columns[7].Tooltip = "Estimated Material";

this.PlanningUnitsGrid.Model.Columns[8].Tooltip = "Schedule A Total";

this.PlanningUnitsGrid.Model.Columns[9].Tooltip = "Actual";

this.PlanningUnitsGrid.Model.Columns[10].Tooltip = "Contract";

this.PlanningUnitsGrid.Model.Columns[11].Tooltip = "Description";

this.PlanningUnitsGrid.Model.Columns[12].Tooltip = "Status";

//PlanningUnits planningUnits = new PlanningUnits();

//lblNavigateUrl.Text = "<a rel='nofollow' rel='nofollow' href='/XWeb-Dev02/customised/general/Pendennis/PSY_Workpackage/Bands/psy_create_wp_norms.aspx?pj=" + Entity.EntityID + "&user=" + UserID + " target='_blank'><i class=\"fas fa-plus fa blue\"></i><span class=\"fa - layers - text fa - inverse\" data-fa-transform=\"shrink - 11.5 rotate--30\" style=\"font=\"Helvetica\" - weight:900\"></span></a>";

//this.gridHidden.DataSource = GetPlanningUnitDetails(false);

//this.gridHidden.DataBind();

this.Session["Parameter"] = Parameter.ToString();

this.Session["Entity"] = Entity.EntityID.ToString();

this.Session["User"] = UserID.ToString();

private void BindGrid()

PlanningUnitsGrid.DataSource = GetPlanningUnitDetails(false);

protected void Grid_ServerExcelExporting(object sender, Syncfusion.JavaScript.Web.GridEventArgs e)

ExcelExport exp = new ExcelExport();

DataView data = (DataView)SqlData.Select(new DataSourceSelectArguments());

var emp = (from DataRow row in dt.Rows

select new PlanningUnits

EXT_Workpackage_ID = Convert.ToInt32(row["EXT_Workpackage_ID"]),

workpackage_code = row["workpackage_code"].ToString(),

name = row["name"].ToString(),

Job = row["Job"].ToString(),

status = row["status"].ToString(),

billing = row["billing"].ToString(),

Allocated_To = row["Allocated_To"].ToString(),

createddate = row["createddate"].ToString(),

earliest_start = row["earliest_start"].ToString(),

last_update = row["last_update"].ToString(),

Duration = Convert.ToInt32(row["Duration"]),

Actual = Convert.ToInt32(row["Actual"]),

child_duration = Convert.ToInt32(row["child_duration"]),

est_mat = Convert.ToInt32(row["est_mat"]),

scheduleatotal = Convert.ToInt32(row["scheduleatotal"]),

contracttype = row["contracttype"].ToString()

//latest_completion = row["latest_completion"].ToString(),

//Entity = Convert.ToInt32(row["Entity"]),

//xm = Convert.ToInt32(row["xm"]),

//xs = Convert.ToInt32(row["xs"]),

exp.Export(PlanningUnitsGrid.Model, (IEnumerable)emp, "Export.xlsx", ExcelVersion.Excel2010, true, true, "flat-lime");

[Exception: Object cannot be cast from DBNull to other types.]
   Syncfusion.JavaScript.Web.CommonDataBoundControl.RaisePostBackEvent(String EventArgument) +443
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +5028