C# 从另一个表单调用方法
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Call a method from another form
提问by BudBrot
I try to call a method from another form. My try:
我尝试从另一种形式调用方法。我的尝试：
public partial class newLedPopUp : Form
{
Form1 back = new Form1();
back.output();
Close();
}
and
和
public partial class Form1 : Form
{
newLedPopUp popup = new newLedPopUp();
public void output()
{
button3_Click(null, null);
}
}
Can somebody help me? I really can't find my error and I've been looking for a very long time.
有人可以帮助我吗？我真的找不到我的错误，我已经找了很长时间了。
采纳答案by Habib
Instead of creating an instance of a new Form, you probably need an instance of already opened form and call the method from there. You can try:
您可能需要一个已经打开的表单实例，并从那里调用该方法，而不是创建新表单的实例。你可以试试：
if (System.Windows.Forms.Application.OpenForms["yourForm"] != null)
{
(System.Windows.Forms.Application.OpenForms["yourForm"] as Form1).Output();
}
plus you can replace calling the button3_Click(null,null)in your Outputmethod, by placing the code of the event in a separate method and then calling that method against your button click event or your public output method
此外，您可以通过将事件代码放在单独的方法中，然后针对按钮单击事件或公共输出方法调用该方法来替换button3_Click(null,null)在您的Output方法中调用
回答by Sergey Berezovskiy
You are closing Form1immediately after calling outputmethod. Thus I assume, you have some business-related, or data access logic there. Try to move code, which is executed on button3_Clickevent handler, to separate object
您Form1在调用output方法后立即关闭。因此，我假设您在那里有一些与业务相关的或数据访问逻辑。尝试将在button3_Click事件处理程序上执行的代码移动到单独的对象
public class Foo
{
public void Output()
{
// move here button3_Click code
}
}
Then create Foo and pass it to both forms (or you can instantiate it inside forms without dependency injection)
然后创建 Foo 并将其传递给两个表单（或者您可以在没有依赖注入的情况下在表单中实例化它）
Foo foo = new Foo();
Form1 form1 = new Form1(foo);
LedPopUp form2 = new LedPopUp(foo);
And use it like this:
并像这样使用它：
public partial class Form1 : Form
{
private Foo _foo;
// without dependency injection: private Foo _foo = new Foo();
public Form1(Foo foo)
{
_foo = foo;
}
protected void button3_Click(object sender, EventArgs e)
{
_foo.Output();
}
}
