Why my recursive function calling itself again after returning the value in c#?

Question

I have function in C#, this is :

public int checkUplinkID(string memID, string original_mem)
{
    string original_memID = original_mem;
    int retValue = 0;
    DataTable dt = new DataTable();
    using (SqlConnection mCon = new SqlConnection())
    {
        mCon.ConnectionString = ConStr;
        try
        {
            mCon.Open();
            using (SqlCommand mCom = new SqlCommand())
            {
                mCom.Connection = mCon;
                mCom.CommandText = "Get_UplinkID";
                mCom.Parameters.AddWithValue("@memID", memID);
                mCom.CommandType = CommandType.StoredProcedure;

                SqlDataAdapter da = new SqlDataAdapter(mCom);
                da.Fill(dt);
                if (dt.Rows.Count > 0 && retValue != 1)
                {
                    string n_upid = dt.Rows[0]["uplineId"].ToString();
                    if (n_upid.ToLower() == original_memID.ToLower())
                    {
                        retValue = 1;

                    }
                    else if( n_upid.ToLower() != original_memID.ToLower())
                    {
                        if (n_upid.ToLower() == "self")
                        {
                            retValue = 0;
                        }
                        else
                        {
                            checkUplinkID(n_upid, original_memID);  // its coming back here after returning and its returning '0' 
                        }
                    }
                }
            }
        }
        catch (Exception ex)
        {
            throw ex;
        }
        finally
        {
            mCon.Close();
            mCon.Dispose();
        }
    }

    return retValue;

}

Now the problem is after the retValue = 1 it's returning but it's going back to the checkUplinkID function and making retValue = 0 and returning it. so what should I do?

And I am calling this function in a aspx.cs page, like this:

 int getchk = iobj.checkUplinkID(memid, memberId); 

Where iobj is object of the class where that method is.

Answer 1

You most likely want to assign the return value of checkUplinkID to retValue :

else
{
    retValue = checkUplinkID(n_upid, original_memID);  // its coming back here after returning and its returning '0' 
}

Oh, and your catch block is very bad style:
It doesn't do anything except removing the original stack trace, so you will have no info on where the exception originally originated from. Just remove that catch block.

Answer 2

If I understand correctly, the result of the recursive call is not used. You need to store the value:

retValue = checkUplinkID(n_upid, original_memID);

Otherwise, the result of the recursive call is not used and the retValue of the "outermost" method call remains 0.

Answer 3

You're forgetting a basic concept of recursion, the BASE case, that is where the recursion stops and go back resolving all the other calls. That's why your recursion didn't stop;