CODEWITHSUNDEEP
c#variablesunassigned-variable
user2510809
user2510809

Reputation: 245

Do you have to initialize a string variable inside a method?

I am programming in C# and I keep getting an error for my string variable result.

When I hover over the line return result it says use of unassigned local variable.

Do I have to assign result a value before I use it? How come i do not get the same error for SqlDataReader reader?

string searchbyLastName(string lastname)
{
    string result; 

    SqlDataReader reader;

    try
    {
        reader = myCommand.ExecuteReader();

        if (reader.HasRows)
        {
            while (reader.Read())
            {
                if (reader["LastName"].ToString() == lastname)
                {
                    result = reader.GetString(0);
                    break;
                }
            }

            return result;
        }
        else 
           return "No results found";
    }
    catch (Exception)
    {
        return("Database Error");
    }
}

Upvotes: 1

Views: 873

Answers (2)

Hans Kesting
Hans Kesting

Reputation: 39329

The compiler needs to know you have definitely assigned a value to a variable, at the point where you are using that value.

In your case reader is always assigned a value (reader = myCommand.ExecuteReader();), but result isn't, because that depends on reader["LastName"].ToString() == lastname being true, which may never happen (even if you designed the system so that in reality you always find a match - the compiler doen't know that).

So somewhere before you enter that while-loop you have to assign a value. result = null would be enough. This value could also be used to signal a "lastname not found" condition to the calling code.

Upvotes: 0

Ed Swangren
Ed Swangren

Reputation: 124760

if (reader["LastName"].ToString() == lastname)

If that is never true then result is not initialized. The SqlDataReader is always initialized prior to being used. Just initialize the string.

var result = "";

Upvotes: 3

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