Cases won't execute in Switch statement...?

Question

I'm trying to attempt something that seems super simple, but right now I want to throw my monitor outside out into the snow. I can't see why my switch statement is not executing when called.

Here it is:

private: System::Void button1_Click(System::Object^  sender, System::EventArgs^  e) // Arithmetic Button Click
         {
            String^ riS = dc1->Text;
            String^ ciS = dc2->Text;        
            colint = int::Parse(dc2->Text);
            std::ostringstream ss;
            String^ answer;
            op1 = Double::Parse(foValue->Text);
            op2 = Double::Parse(soValue->Text);

            // Enter switch 
            switch(op_sym)
    {
        case '+':

            sum = op1 + op2;
            DGV->CurrentCell = DGV->Rows[RI]->Cells[CI];
            ss << sum;
            answer = Convert::ToString(answer);
            MessageBox::Show(answer);
            DGV->CurrentCell->Value = answer;
            sumLabel->Text = "TEST";
            break;

        case '-':
            sum = op1 - op2;
            break;
        case '*':
            sum = op1 * op2;
            break;
        case '/':
            if (op2 == 0)
            {
                MessageBox::Show("Sorry, you cannot divide by zero \n Please, reselect yoru second cell operand");
                secondOpText->Text = "";
            }
            else
            {
            sum = op1/op2;
            }
            break;
        default:
            MessageBox::Show("I'm sorry.  Please select one of these four arithmetic symbols from the drop down list: \n +, -, *, /");
            break;
    }


         }

I'm getting the op_sym from right above:

private: System::Void comboBox1_SelectedIndexChanged(System::Object^  sender, System::EventArgs^  e) 
         {
             Object^ selectedItem = comboBox1->SelectedItem;
             String^ cb = selectedItem->ToString();
             if( cb = "+")
             {
                op_sym = '+';
             }
             if(cb = "-")
                 op_sym = '-';
             if(cb = "/")
                 op_sym = '/';
             if(cb = "*")
                 op_sym = '*';

         }

op_sym has already been declared as a char at the top. If someone would inform me of my most likely, beginner's mistake, I would be much appreciate. Thanks.

EDIT

...
    case '+':
                {
                sum = op1 + op2;
                DGV->CurrentCell = DGV->Rows[RI]->Cells[CI];
                ss << sum;
                answer = Convert::ToString(sum);
                MessageBox::Show( answer);
                DGV->CurrentCell->Value = answer;
                sumLabel->Text = answer;
                break;
                }
...


private: System::Void comboBox1_SelectedIndexChanged(System::Object^  sender, System::EventArgs^  e) 
         {
             Object^ selectedItem = comboBox1->SelectedItem;
             String^ cb = selectedItem->ToString();
             if( cb == "+")
             {
                op_sym = '+';
             }
             if(cb == "-")
                 op_sym = '-';
             if(cb == "/")
                 op_sym = '/';
             if(cb == "*")
                 op_sym = '*';
}

Answer 1

Notice in your second function (comparing the actual value of the op_sym):

 if( cb = "+")
         {
            op_sym = '+';
         }
         if(cb = "-")
             op_sym = '-';
         if(cb = "/")
             op_sym = '/';
         if(cb = "*")
             op_sym = '*';

You're performing assignments to cb and not actually comparisons. Try using the == operator for comparing two values:

if ( cb == "+" )
...

When you want to change the value of the op_sym, you use the assignment operator (=). When you want to compare values of String's, use the comparison operator (==).

Also - Check out the API for working with String is VC++: http://msdn.microsoft.com/en-us/library/ms177218.aspx