Fix To: The Out Parameter Must Be Assigned to Before Control Leaves the Current Method

In this blog you will learn a fix to "the out parameter must be assigned to before control leaves the current method."

Introduction

• The out keyword causes arguments to be passed by reference.
• To use an out parameter, both the method definition and the calling method must explicitly use the out keyword.
• Although variables passed as out arguments do not have to be initialized before being passed, the called method is required to assign a value before the method returns.

Example

Simple Program to check whether the given character exists or not,

using System;

class Program
{
    static void Main ( )
    {
        bool sharpsymbol; // Used as out parameter.
        bool AndSymbol;
        bool Paranthesis;
        const string value = "& # @";// Used as input string.

        CheckString ( value, out sharpsymbol, out AndSymbol, out Paranthesis );

        Console.WriteLine ( value ); // Display value.
        Console.Write ( "sharpsymbol: " ); // Display labels and bools.
        Console.WriteLine ( sharpsymbol );
        Console.Write ( "AndSymbol: " );
        Console.WriteLine ( AndSymbol );
        Console.Write ( "Paranthesis: " );
        Console.WriteLine ( Paranthesis );
        Console.ReadLine ( );
    }

    static void CheckString ( string value,
    out bool sharpsymbol,
    out bool AndSymbol,
    out bool Paranthesis )
    {
        // Assign all out parameters to false.


        sharpsymbol = AndSymbol = Paranthesis = false;

        for(int i = 0; i < value.Length; i++)
        {
            switch(value[i])
            {
                case '#':
                    {
                        sharpsymbol = true; // Set out parameter.
                        break;
                    }
                case '&':
                    {
                        AndSymbol = true; // Set out parameter.
                        break;
                    }
                case '(':
                    {
                        Paranthesis = false; // Set out parameter.
                        break;
                    }
            }
        }
    }
}

Output



When the Problem Occurs.



Note

In the above program, even though you assigned the out variable value inside the looping/case statement, if you don't assign any value in the method definition like the above snagit then you will get the following error:



Conclusion

I hope the above information is useful for beginners, kindly let me know your thoughts.