Warning given when debugging source code in visual studio 2010

Question

I had set breakpoint in source code but it will give me warning that source code is different from original one. It will not hit breakpoint.Hit location to allow change in source code. can anybody explain me waht is problem?

Answer 1

Checksum of source code file doesn't match checksum into the PDB file.

To solve that rebuild the solution.

Workaround: In Location property of a breakpoint check Allow source code to be different

Answer 2

This can happen when you compile & run a release build. In Release builds the compiler makes optimizations that may change or delete portions of code, take this example:

static void Main()
{
    int x = 10 + 5;   // <---- BREAKPOINT HERE

    Console.WriteLine("Foo");
}

If you compile & run that code in a debug build, the breakpoint will be hit as usual. In a release build, the compiler will see that 'x' is never used, and will "optimize away" the entire line, which means the breakpoint will never be hit!