ASP.NET ReportViewer表达式返回错误

Question

I have a ASP.NET Report viewer.

In report I have the following expression:

="Total for Region: " & 
 iif(str(Fields!Region_Of_Responsibility.Value)="","No Region",Fields!Region_Of_Responsibility.Value)

In run time I return #Error.

Why this error happens and how find what this #Error means?

Answer 1

I wonder if this column can contain nulls, and if so, here's another way to tackle this one

="Total for Region: " & 
 iif(cstr(Fields!Region_Of_Responsibility.Value)="" or isDbNull(Fields!Region_Of_Responsibility.Value),"No Region",Fields!Region_Of_Responsibility.Value)