I tried the statement: dataset1.SelectQuery[i].column1 == null and I got the
error:
System.Data.StrongTypingException was unhandled
Message="The value for column 'TaxType' in table 'TaxSelect' is DBNull."
Source="Retail"
StackTrace:
at Retail.dsTaxRate.TaxSelectRow.get_TaxType() in C:\Documents and
Settings\HP_Owner\My Documents\Visual Studio
2005\Projects\Retail\Retail\dsTaxRate.Designer.cs: line 516
at Retail.frmPayrollSetUp.LoadComboBox(ComboBox cmb, String taxType)
in C:\Documents and Settings\HP_Owner\My Documents\Visual Studio
2005\Projects\Retail\Retail\frmPayrollSetUp.cs:lin e 83
at Retail.frmPayrollSetUp.frmPayrollSetUp_Load(Object sender,
EventArgs e) in C:\Documents and Settings\HP_Owner\My Documents\Visual Studio
2005\Projects\Retail\Retail\frmPayrollSetUp.cs:lin e 33
at System.Windows.Forms.Form.OnLoad(EventArgs e)
at System.Windows.Forms.Form.OnCreateControl()
at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)
at System.Windows.Forms.Control.CreateControl()
at System.Windows.Forms.Control.WmShowWindow(Message& m)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ScrollableControl.WndProc(Mes sage& m)
at System.Windows.Forms.ContainerControl.WndProc(Mess age& m)
at System.Windows.Forms.Form.WmShowWindow(Message& m)
at System.Windows.Forms.Form.WndProc(Message& m)
at
System.Windows.Forms.Control.ControlNativeWindow.O nMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.W ndProc(Message& m)
at System.Windows.Forms.NativeWindow.DebuggableCallba ck(IntPtr hWnd,
Int32 msg, IntPtr wparam, IntPtr lparam)
at System.Windows.Forms.SafeNativeMethods.ShowWindow( HandleRef hWnd,
Int32 nCmdShow)
at System.Windows.Forms.Control.SetVisibleCore(Boolea n value)
at System.Windows.Forms.Form.SetVisibleCore(Boolean value)
at System.Windows.Forms.Control.set_Visible(Boolean value)
at
System.Windows.Forms.Application.ThreadContext.Run MessageLoopInner(Int32
reason, ApplicationContext context)
at
System.Windows.Forms.Application.ThreadContext.Run MessageLoop(Int32 reason,
ApplicationContext context)
at System.Windows.Forms.Form.ShowDialog(IWin32Window owner)
at System.Windows.Forms.Form.ShowDialog()
at Retail.frmMain.frmMain_Load(Object sender, EventArgs e) in
C:\Documents and Settings\HP_Owner\My Documents\Visual Studio
2005\Projects\Retail\Retail\frmMain.cs:line 22
at System.Windows.Forms.Form.OnLoad(EventArgs e)
at System.Windows.Forms.Form.OnCreateControl()
at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)
at System.Windows.Forms.Control.CreateControl()
at System.Windows.Forms.Control.WmShowWindow(Message& m)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ScrollableControl.WndProc(Mes sage& m)
at System.Windows.Forms.ContainerControl.WndProc(Mess age& m)
at System.Windows.Forms.Form.WmShowWindow(Message& m)
at System.Windows.Forms.Form.WndProc(Message& m)
at
System.Windows.Forms.Control.ControlNativeWindow.O nMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.W ndProc(Message& m)
at System.Windows.Forms.NativeWindow.DebuggableCallba ck(IntPtr hWnd,
Int32 msg, IntPtr wparam, IntPtr lparam)
at System.Windows.Forms.UnsafeNativeMethods.SendMessa ge(HandleRef
hWnd, Int32 msg, Int32 wParam, Int32 lParam)
at System.Windows.Forms.Form.SetVisibleCore(Boolean value)
at System.Windows.Forms.Control.set_Visible(Boolean value)
at
System.Windows.Forms.Application.ThreadContext.Run MessageLoopInner(Int32
reason, ApplicationContext context)
at
System.Windows.Forms.Application.ThreadContext.Run MessageLoop(Int32 reason,
ApplicationContext context)
at System.Windows.Forms.Application.Run(Form mainForm)
at Retail.Program.Main() in C:\Documents and Settings\HP_Owner\My
Documents\Visual Studio 2005\Projects\Retail\Retail\Program.cs:line 33
at System.AppDomain.nExecuteAssembly(Assembly assembly, String[] args)
at System.Runtime.Hosting.ManifestRunner.Run(Boolean checkAptModel)
at System.Runtime.Hosting.ManifestRunner.ExecuteAsAss embly()
at
System.Runtime.Hosting.ApplicationActivator.Create Instance(ActivationContext
activationContext, String[] activationCustomData)
at
System.Runtime.Hosting.ApplicationActivator.Create Instance(ActivationContext
activationContext)
at
Microsoft.VisualStudio.HostingProcess.HostProc.Run UsersAssemblyDebugInZone()
at System.Threading.ThreadHelper.ThreadStart_Context( Object state)
at System.Threading.ExecutionContext.Run(ExecutionCon text
executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()
--
L. A. Jones
"Cor Ligthert [MVP]" wrote:
>
Hi Dave,
if (dataset1.SelectQuery[i].column1 == null) // there is a null value
Cor
"Dave" <Da**@discussions.microsoft.comschreef in bericht
news:25**********************************@microsof t.com...
If Iwant to check if dataset1.SelectQuery1[i].column1 ==
System.DBNull.Value. How do I do this? What I wrote above will give an
error.
--
L. A. Jones