c# - 当前上下文中不存在名称“btn2”

Question

下面我放了部分代码，问题是 btn2.tag。它说“当前上下文中不存在名称'btn2'”我该如何解决这个问题？什么是（是）方式？

    public Main()
    {
        InitializeComponent();

        // bla bla bla

        int NumOfButtons = 12;

        int loc = 20; 
        int k = 5;

        for (int i = 1; i <= NumOfButtons; i++)
        {
            Button btn = new Button();
            {
                lst.Location = new Point(4, 4);
                btn.Size = new Size(55, 55);
                btn.Tag = i;

                command.CommandText = "select product_Name from T_Product where PRODUCT_ID = " + btn.Tag;
                btn.Text = command.ExecuteScalar().ToString();  

                btn.Location = new Point(k, loc);
            }


            btn.Click += Buttons_Click;  

    }

    private void Buttons_Click(System.Object sender, System.EventArgs e)
    {
        isclicked = true;
        // Used "Sender" to know which button was clicked ?
        Button btn = sender as Button;

        Button btn2 = sender as Button;
        btn2.Tag = btn.Tag;


    }

    private void button5_Click(object sender, EventArgs e)
    {
        if (textBox1.Text != "")
        {
            SqlConnection conn = new SqlConnection(@"server=.\SQLEXPRESS;Initial Catalog=DUK1;Integrated Security=True;Pooling=False");
            command.Connection = conn;
            conn.Open();      
            command.CommandText = "select product_PRIZE from T_Product where PRODUCT_ID = " + btn2.Tag;   // here problem occurs

            textBox5.Text = comando.ExecuteScalar().ToString();
        }

}

//////

在这个例子中我有一些按钮（12），当我点击 button5 时，当我点击 button5 时，我想根据 btn2.Tag（这是 12 个按钮的标签之一）显示奖品。

我将如何做到。

Answer 1

我认为这就是你想要的：

object tag;
private void Buttons_Click(System.Object sender, System.EventArgs e)
{
    isclicked = true;
    // Used "Sender" to know which button was clicked ?
    Button btn = sender as Button;      
    tag = btn.Tag;
}

private void button5_Click(object sender, EventArgs e)
{
    if (textBox1.Text != "")
    {
        SqlConnection conn = new SqlConnection(@"server=.\SQLEXPRESS;
        Initial Catalog=DUK1;Integrated Security=True;Pooling=False");
        command.Connection = conn;
        conn.Open();      
        command.CommandText = "select product_PRIZE from T_Product where PRODUCT_ID = '" + tag != null ? tag : "" + "'";
        textBox5.Text = comando.ExecuteScalar().ToString();
    }
 }