It seems that because datetime is a value type it is impossible to save a null value. If you use 2-way databinding in formview for saving dates. You will have problems even when just using a calendar control. This is the solution I found to my problem
In the html view change the Bind(”Date_Column”) into Eval(”Date_Column”)
<
asp:TextBox ID=”Timesheet_DateTextBox” runat=”server” Text=’‘ Width=”124px”>FONT color=#800000>asp:TextBox>
should then become
<
asp:TextBox ID=”Timesheet_DateTextBox” runat=”server” Text=’‘ Width=”124px”>FONT color=#800000>asp:TextBox>
I also want to store null values for unentered dates. A string you can null but this will give an exception like : System.String not a valid DateTime
i.e. for the objectdatasource inserting event i do it :
protected
void odsTimesheet_Inserting(object sender, ObjectDataSourceMethodEventArgs e)
{
e.InputParameters[0] = Guid.NewGuid();
e.InputParameters[4] = SetDate(“Timesheet_DateTextBox”);
}
private object SetDate(string controlname)
{
TextBox tb = (TextBox)fvProject.FindControl(controlname);
return (tb.Text.Trim().Length == 0) ? (object)null : (object)DateTime.Parse(tb.Text);
}
If someone knows a better solution or a codeless one please let me know.
