Comments on: Saving server control properties to ViewState with custom attributes

By: Jeff G.

Jeff G. — Tue, 17 Nov 2009 13:38:40 +0000

There’s a more efficient way to do this in the recent version of C#:

public class PieControl1 : Control
{
…
public int Pies
{
get { return (int) (ViewState["Pies"] ?? 0); }
set { ViewState["Pies"] = value; }
}
}

The new ?? operator says, “Use the value if it is not null, or else use the second operand if it is.” So if ViewState["Pies"] is null, a 0 will be returned. Otherwise, the value of ViewState["Pies"] will be returned.

By: Jim West

Jim West — Tue, 28 Jul 2009 13:14:53 +0000

Nice work, I made a slight alteration to your LoadViewstate method to enable use of the default value attribute:

if (ViewState[property.Name] != null)
property.SetValue(this, ViewState[property.Name], null);
else
{
// Load the default value instead
attributes = property.GetCustomAttributes(typeof(DefaultValueAttribute), true);
if (attributes.Length > 0)
{
DefaultValueAttribute dva = (DefaultValueAttribute)attributes[0];
property.SetValue(this, dva.Value, null);
}

}

By: House

House — Wed, 03 Jun 2009 14:05:59 +0000

Really useful, thanks.

By: Ting Zwei Kuei

Ting Zwei Kuei — Thu, 01 Jan 1970 00:00:00 +0000

Good idea, wondered why Microsoft didn’t implement this.