Why will this query not accept null values, it accepts mm/dd/yyyy but when I dont' entered anything it says datetime not valid. My database column is also set to allow null. You can try this query out yourself if you want because it works with Northwind.
public
partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Button1_Click(object sender, EventArgs e)
{
//Create new instance
DataClassesDataContext db = new DataClassesDataContext();
//Search by ?
var qry =
from s in db.Employees
where (
s.BirthDate >=
Convert.ToDateTime(txtFrom.Text) || (String.IsNullOrEmpty(txtFrom.Text))
&& s.BirthDate <
Convert.ToDateTime(txtTo.Text) || (String.IsNullOrEmpty(txtTo.Text))
)
select new { s.EmployeeID, s.BirthDate };
GridView1.DataSource = qry;
GridView1.DataBind();
}
}
<
body>
<form id="form1" runat="server">
<div>
BirthDate From
<asp:TextBox ID="txtFrom" runat="server"></asp:TextBox>
<br />
BirthDate To
<asp:TextBox ID="txtTo" runat="server"></asp:TextBox>
</div>
<asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Search" />
<asp:GridView ID="GridView1" runat="server">
</asp:GridView>
</form>
</
body>
