ReportParameterInfo.AllowBlank Property
Visual Studio 2010
Indicates whether an empty string is a valid value for the parameter. Read-only.
Namespace: Microsoft.Reporting.WebForms
Assembly: Microsoft.ReportViewer.WebForms (in microsoft.reportviewer.webforms.dll)
Assembly: Microsoft.ReportViewer.WebForms (in microsoft.reportviewer.webforms.dll)