My name
is
Jon Skeet

Using statement with unknown implementation?

Can the following code be translated into using the... ejem... 'using' statement?

TextReader TheReader;
if( UploadedFile ) { TheReader = new System.IO.StreamReader( LocalFileName ); }
else { TheReader = new System.IO.StringReader( Input ); }
//Use The reader
TheReader.Close();

So using (TextReader TheReader = ??)

Well you could use the conditional operator:

// Variable names changed for convention, and fully-qualified names simplified
using (TextReader reader = uploadedFile ? File.OpenText(localFileName)
                                        : (TextReader) new StringReader(input))
{
    ...
}

The cast to TextReader can be on either of the last two operands - it's just to let the compiler know the type of the expression, as it can't just find the common type (TextReader) from StreamReader (the 2nd operand) and StringReader (the third).

You could assign the variable before the using statement as per Guffa's answer - but personally I'd use this code, to keep the scope of the variable limited to the using statement.

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