一、编码思路

在父窗体使用Lambda表达式自定义事件赋给子窗体内定义的事件，通过在子窗体内调用事件实现传参

二、传递的参数

创建文件SomeUtility.cs，在类SomeUtility中声明结构ReturnStruct

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace EventTest
{
    public class SomeUtility
    {
        public struct ReturnStruct
        {
            public string sData1;
            public string sData2;
            public string sData3;
            public ReturnStruct(string s1, string s2, string s3)
            {
                sData1 = s1;
                sData2 = s2;
                sData3 = s3;
            }
        }
    }
}

三、子窗体相关

窗体FormTip，里面有三个TextBox，单击确定会将三个TextBox的值传递到父窗体中

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace EventTest
{
    public partial class FormTip : Form
    {
        public class TEventArgs<T> : EventArgs
        {
            public T Args
            {
                get;
                private set;
            }

            public TEventArgs(T args)
            {
                this.Args = args;
            }
        }

        [Browsable(false)]
        internal event EventHandler<TEventArgs<SomeUtility.ReturnStruct>> EventTest;

        SomeUtility.ReturnStruct rs;
        public SomeUtility.ReturnStruct GetReturnStruct()
        {
            return rs;
        }

        //构造函数1：无参数
        public FormTip()
        {
            InitializeComponent();
        }

        //构造函数2：有一个ReturnStruct类型参数
        public FormTip(SomeUtility.ReturnStruct r)
        {
            InitializeComponent();
            this.rs.sData1 = r.sData1;
            this.rs.sData2 = r.sData2;
            this.rs.sData3 = r.sData3;
        }

        private void FormTip_Load(object sender, EventArgs e)
        {
            this.txtData1.Text = rs.sData1;
            this.txtData2.Text = rs.sData2;
            this.txtData3.Text = rs.sData3;
        }

        //单击“确定”按钮：调用事件EventTest
        private void btnOK_Click(object sender, EventArgs e)
        {
            //调用事件EventTest
            if (this.EventTest != null)
            {
                SomeUtility.ReturnStruct rs = new SomeUtility.ReturnStruct(
                    this.txtData1.Text, this.txtData2.Text, this.txtData3.Text);
                this.EventTest(this, new TEventArgs<SomeUtility.ReturnStruct>(rs));
            }
            //退出窗口
            this.Close();
        }

        //单击“取消”按钮：直接退出
        private void btnCancel_Click(object sender, EventArgs e)
        {
            this.Close();
        }
    }
}

四、父窗体相关

窗体FormMain，单击按钮btnTest打开子窗体，并在单击子窗体的“确定”按钮后根据子窗体内设置的值更新txtResult中的文本内容

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace EventTest
{
    public partial class FormMain : Form
    {
        public FormMain()
        {
            InitializeComponent();
        }

        private void FormMain_Load(object sender, EventArgs e)
        {
            this.txtResult.Text = "1:- 2:- 3:-";
        }

        private void btnTest_Click(object sender, EventArgs e)
        {
            SomeUtility.ReturnStruct rsTest = 
                new SomeUtility.ReturnStruct("Data1", "Data2", "Data3");
            FormTip frmTip = new FormTip(rsTest);

            frmTip.EventTest += (obj, args) =>
            {
                SomeUtility.ReturnStruct rsTemp = frmTip.GetReturnStruct();
                rsTest.sData1 = args.Args.sData1;
                rsTest.sData2 = args.Args.sData2;
                rsTest.sData3 = args.Args.sData3;
                this.txtResult.Text = string.Format("1:{0} 2:{1} 3:{2}",
                    rsTest.sData1, rsTest.sData2, rsTest.sData3);
                MessageBox.Show("赋值成功");
            };

            frmTip.ShowDialog();
        }
    }
}

五、运行示例

1）打开父窗体FormMain

2）打开子窗体FormTip，输入三个值

3）将三个值传回父窗体FormMain

END

C# 一个子窗体向父窗体传递参数的例子