Careful with IIF in VB.NET

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In VB.NET, We generally use ternary operator, IIF. Today we came across with some atypical behaviors.

 Dim a As Boolean = True 
        Dim b As Integer = 1 
        Dim c As Integer = Nothing   
        Dim d As Integer = CInt(IIf(a = True, b = 3, c.ToString()))  
What is the result?
It throws error. Null cannot be converted to string.
 But if we use same statements with IF..ELSE, it will give you correct result.

If (a = True) Then 
            b = 3 
        Else 
            Response.Write(c.ToString()) 
        End If 
It works fine.
First observation:  In IIF, it evaluates both true and false conditions. That’s why it gives error.

Another example:
 Dim a As Boolean = True 
        Dim b As Integer = 1 
        Dim c As Integer = 2   
        Dim d As Integer = CInt(IIf(a = True, b = 3, c=4))  
What is the value of B now?
It should be 3, right?

But, it will be 1. Yes One 

Second observation:
a= true is right, so it goes to b=3 statement. 
But it won’t consider it as assignment, instead it treats as conditional EQUAL operator. So b= 3 means is 1=3 ? 
Obviously 1 is not equal to 3. So it returns false, which is 0.

Note: When Visual Basic converts numeric data type values to Boolean, 0 becomes False and all other values become True.

So my dear folks, please be careful while using IIF in VB.NET. Few things seems to be simple but very dangerous.

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