Question

我有一系列按钮和标签数组： Label[] labels = new Label[10]; Button[] but = new Button[10];

在点击另一个按钮时，我想从数组中动态创建新按钮和新标签，我也想要[i]更改标签的tex [i]：

    private void button1_Click(object sender, EventArgs e)
    {
        labels[i] = new Label();
        labels[i].Location = new System.Drawing.Point(0, 15+a);
        labels[i].Parent = panel1;
        labels[i].Text = "Sample text";
        labels[i].Size = new System.Drawing.Size(155, 51);
        labels[i].BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle;
        a = labels[i].Height + labels[i].Top;

        but[i] = new Button();
        but[i].Text = "-";
        but[i].Location = new System.Drawing.Point(0, labels[i].Height + labels[i].Top);
        but[i].Parent = panel1;
        but[i].Size = new System.Drawing.Size(155, 10);
        but[i].Click += new System.EventHandler(but_Click);
        i++;
    }
    private void but[i]_Click(object sender, EventArgs e)
    {
        labels[i].Text = "Changed Text";
    }

但显然我不能在事件处理程序中放入一个数组，那我该怎么做呢？

Answer 1

这样做的一种方法是让你的方法返回一个处理程序而不是一个处理程序：

private EventHandler but_Click(int i)
{
    return (s, e) => labels[i].Text = "Changed Text";
}

并使用它：

but[i].Click += but_Click(i);

或者内联：

but[i].Click += (s, ea) => labels[i].Text = "Changed Text";

在其中任何一个中发生的是一些编译器魔术来捕获i变量。它等同于此（这也是一种有效的，如果详细的方式）：

class MyWrapper {
    private int i;
    public MyWrapper(int i) {
        this.i = i;
    }
    public void TheHandler(object sender, EventArgs e) {
        // TODO: capture the object that owns `labels` also, or this won't work.
        labels[i].Text = "Changed Text";
    }
}

//call with
but[i].Click += new EventHandler(new MyWrapper(i).TheHandler);

Answer 2

您可以将数组索引作为Tag属性添加到按钮，然后在but_Click中将其拉回。

所以，添加

but[i].Tag = i;

创建按钮。然后更改事件处理程序：

private void but_Click(object sender, EventArgs e)
{
    int buttonIndex = (int)((Button)sender).Tag;
    labels[buttonIndex].Text = "Changed Text";
}

或者将事件处理程序内联：

but[i].Click += (s,e) => { label[i].Text = "Changed Text"; }

使用Tag属性的其他选项，添加：

but[i].Tag = label[i];

...

private void but_Click(object sender, EventArgs e)
{
    Label label = (Label)((Button)sender).Tag;
    label.Text = "Changed Text";
}

这种方法的优点是您在初始创建控件后不依赖于保持数组同步。

Answer 3

我想这是自我解释的：

public void SomeMehthod()
{
    Button btn1 = new Button();
    Button btn2 = new Button();
    Button btn3 = new Button();

    // Your button-array
    Button[] btns = new Button[]
    {
        btn1,
        btn2,
        btn3
    };

    foreach(Button btn in btns)
    {
        // For each button setup the same method to fire on click
        btn.Click += new EventHandler(ButtonClicked);
    }
}

private void ButtonClicked(Object sender, EventArgs e)
{
    // This will fire on any button from the array
    // You can switch on the name, or location or anything else
    switch((sender as Button).Name)
    {
        case "btn1":
            // Do something
            break;
        case "btn2":
            // Do something
            break;
        case "btn3":
            // Do something
            break;
    }
}

或者，如果你的数组可以访问全球：

Button[] btns = new Button[5];
Label[] lbls = new Label[5];

private void ButtonClicked(Object sender, EventArgs e)
{
    Button clicked = sender as Button;
    int indexOfButton = btns.ToList().IndexOf(clicked);

    // ..IndexOf() returns -1 if nothign is found
    if(indexOfButton > 0)
    {
        lbls[indexOfButton].DoWhatYouWant...
    }
}

如何动态创建按钮并向其添加事件？

3 个答案: