To get Fault exception on client side

Question

I am new to WCF and trying to build a demo WCF project with WebHttpBinding binding.

The projects work fine but I am stuck with concept of fault exception. Below is the code I am using to generate fault exception but on client side what I get is (400) Bad Request error and the InnerException is null. Where am I getting wrong?

    public DataTable GetCreativesData(string id,string type)
    {
        try { 
        DataAccess da = new DataAccess();
        string qryStr = @"select * from dbo.tbMyTable";
        if (type != null && type != "")
            qryStr += " WHERE1 type='"+type+"'";
        DataTable dt = da.GetDataTable(qryStr);
        return dt;
        }

       catch (FaultException ex) {
            throw new FaultException("Improper Query");
        }
     }

Answer 1

A 400 error is correct for a fault exception, since you are indicating to the user that something is wrong likely with what they provided.

There is no inner exception when you raise the FaultException, since a core concept of FaultException is that it works across technologies (interoperability) & the concept of an inner exception is very specific to .NET.

If you really wanted to pass an Exception down, you could use the FaultException which allows you to specify a generic parameter and then you set that to Exception. You would then create and raise that.

Another aspect to remember is how you are handling your errors, in your code you are throwing a brand new exception. That means that all the information in the variable ex, is lost. Unless you intend to hide something, you could try this

catch (FaultException ex) 
{
    throw;
}

This option takes the original FaultException and raises it again, thus preserving all the information in it.

Lastly and outside your question, that SQL scares me - looks like it could be vulnerable to a SQL injection attack - just something you may want to check.