C# CodeGeneration variable as type

Question

In an existing application, code is generated to perform a cast, like below: (the types are also generated classes, I provide an example with just object and string)

object o;
string s = (string)o;

When o is of type int, an InvalidCastException is thrown. Therefore, I want to change the code into:

object o;
string s = o as string;

and check later on whether string s is null.

The System.CodeDom is used to perform the code generation. The cast is generated using the CodeCastExpression Class.

I cannot find a way to generate the variable as type way... Can someone help me out? Thanks!

Answer 1

What about using System.ComponentModel.TypeConverter. It has methods to check whether it CanConvertFrom(Type) and CanConvertTo(Type) and has the "universal" ConvertTo Method which accepts an Object in and gives an Object back:

public Object ConvertTo(
    Object value,
    Type destinationType
)

Have a look here: http://msdn.microsoft.com/en-us/library/system.componentmodel.typeconverter.aspx

Answer 2

Maybe you want to try this instead:

//For string...
string s = (o == null ? null : o.ToString());
//For int...
int i = (o == null ? 0 : Convert.ToInt32(o));

Maybe you can just put an if statement before so the code would read:

TheType s = null;

if (o is TheType)
    s = (TheType)o

This will only work with non-value-types. See this post for information on how to accomplish the "is" operator.