public void score(int calcScore)
{
    lblScore.Text += calcScore.ToString();
}

private void square_DragDrop(object sender, DragEventArgs e)
{
    if(shape.Contains("Square"))
    {
        int calcScore = 0;
        calcScore++;
        score(calcScore);
    }
}

private void circle_DragDrop(object sender, DragEventArgs e)
{
    if(shape.Contains("Circle"))
    {
        int calcScore = 0;
        calcScore++;
        score(calcScore);
    }
}

public void score(int calcScore)
{
    int totalScore =0;
    totalScore = totalScore + calcScore;
    lblScore.Text += totalScore.ToString();
}