是真的函數與調用它

Question

private void calcu(double a,int x) 
{ 
    a=Convert.ToDouble(textBox1.Text); 
    textBox1.Clear(); 
} 


private void button26_Click(object sender, EventArgs e) 
{ 
    calcu(a,1); 
} 

Answer 1

你們是不是要分配變量a從button26_Click方法在calcu方法？

如果是這樣，你需要改變你的代碼位：

private void calcu(out double a, int x) 
{ 
    a = Convert.ToDouble(textBox1.Text); 
    textBox1.Clear(); 
} 


private void button26_Click(object sender, EventArgs e) 
{ 
    double a; 
    calcu(out a, 1); 
    // Do something with `a` 
} 

更好的是，爲什麼不把它的功能？

private double calcu(int x) 
{ 
    var a = Convert.ToDouble(textBox1.Text); 
    textBox1.Clear(); 
    return a; 
} 

private void button26_Click(object sender, EventArgs e) 
{ 
    double a = calcu(1); 
    // Do something with `a` 
} 

Answer 2

private void calcu(double a,int x) 
{ 
    a=Convert.ToDouble(textBox1.Text); 
    textBox1.Text = ""; 
} 


private void button26_Click(object sender, EventArgs e) 
{ 
    calcu(a,1); 
}