在表单和UserControl之间传递值 [英] Passing value between forms and UserControl

问题描述

我的项目中有多个表单，在主表单中，我有一个UserControl实例，一个按钮和一个标签，当我按下按钮时，打开第二个表单并在标签中设置数据库中的值，在form2中按OK，值将传递到表单1上的标签.

I have in my project multiple forms, In the main form i have an instance of an UserControl, a button and a label, when I press the button is open the second form and set in a label a value from the database, press OK from form2, the value in passed to a label on form 1.

How i can get the same value in a label in my instance of usercontrol?

推荐答案

您需要在UserControl中添加一个事件，并在该事件发生时触发该事件.设置并确认.我们将此事件称为ValueSet.

You need to add an event to your UserControl and fire this event when a value is set and confirmed. Let''s call this event ValueSet.

public class ValueSetEventArgs : System.EventArgs {
    internal ValueSetEventArgs(string value) { this.fValue = value; }
    public string FValue { get {return fValue; } }
    string fValue;
} //class ValueSetEventArgs

//...

public class MyUserControl {

    //...

    public System.EventHandler<ValueSetEventArgs> ValueSet;
    void SetValue(string value) {
        //do what you already did...
        if (this.ValueSet != null)
            this.ValueSet.Invoke(this, new ValueSetEventArgs(value));
    } //SetValue

} //class MyUserControl

您的表格#1应该将事件处理程序添加到MyCustomControl的此实例.此事件可以设置标签的值或其他任何值:

You form #1 should add an event handler to this instance of your MyCustomControl. This event can set the value of your label or whatever else:

class MyForm Form {
    
    public MyForm {
        InitializeComponent();
        MyUserControl.ValueSet += (sender, eventArgs) => {
            MyLabel.Text = eventArgs.Value;
            // or whatever else
        } //MyUserControl.ValueSet
    } //MyForm

    //...

    // normally called in InitializeComponent,
    // I just show it as manual code:
    Label MyLabel = new Label();
    MyUserControl MyUserControl = new MyUserControl();

} //class MyForm

问题解决了.

—SA

Problem solved.

—SA

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