ASP.NET Grid Tip: How To Check For Empty Values In Header Filter

Here’s a quick and useful tip for finding empty values when using the ASPxGridView’s header filter. For example, if you have a Date column:

And you want to find all the Orders which have an ‘Empty’ ShippedDate value, then follow these 2 simple steps:

1. Override the ASPxGridView’s HeaderFilterFillItems event
2. Add the following 2 lines of code:

C# Version:

protected void ASPxGridView1_HeaderFilterFillItems(object sender, DevExpress.Web.ASPxGridView.ASPxGridViewHeaderFilterEventArgs e)
{
  e.Values.Insert(1, new FilterValue("Empty", "", "[" + e.Column.FieldName + "] Is Null"));
  e.Values.Insert(2, new FilterValue("Not Empty", "", "[" + e.Column.FieldName + "] Is Not Null"));
}

VB.NET Version:

  Protected Sub ASPxGridView1_HeaderFilterFillItems(ByVal sender As Object, ByVal e As DevExpress.Web.ASPxGridView.ASPxGridViewHeaderFilterEventArgs) Handles ASPxGridView1.HeaderFilterFillItems
    e.Values.Insert(1, New FilterValue("Empty", "", "[" & e.Column.FieldName & "] Is Null"))
    e.Values.Insert(2, New FilterValue("Non Empty", "", "[" & e.Column.FieldName & "] Is Not Null"))
  End Sub

This code create 2 new filter values for ‘Empty’ and ‘Not Empty’ which check if the field value is null:

Custom Filter

By using this event, you can also create custom filters which:

• Check if a certain field value is greater 50
• Choose which columns to add the custom filters
• And more…

How? Check out the FilterValue Constructor help topic.

Sample Project

Here’s the sample project which contains both C# and VB.NET versions of the code. Click here to download: [GridCustomHeaderFilter.zip]

Then drop me a line here and let me know what you think of this tip.

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