C# 子窗体与父窗体之间几种传值的方式

做了很多项目，很多项目都用到子父窗体之间的传值。。

父窗体传入子窗体都比较简单，而子窗体传入父窗体因为有很多不通道的需求，所以·搞起来有点头大。

先说父窗体传入子窗体：

将父窗体控件上的值传入子窗体的控件上：

Form1为父窗体

Form2为子窗体

Form1 单击按钮打开Form2，Form2关闭的时候把值传到Form1的控件上

代码：

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 WindowsFormsApplication3
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Form2 f2 = new Form2(this.textBox1.Text);
            if (f2.ShowDialog() == DialogResult.OK)
            {
                this.textBox1.Text = f2.TextBoxValue;
                f2.Close();
            }

        }

    }
}

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 WindowsFormsApplication3
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Form2 f2 = new Form2(this.textBox1.Text);
            if (f2.ShowDialog() == DialogResult.OK)
            {
                this.textBox1.Text = f2.TextBoxValue;
                f2.Close();
            }

        }

    }
}

Form2的代码：

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 WindowsFormsApplication3
{
    public partial class Form2 : Form
    {
        public Form2():this(null)
        {

        }

        public string TextBoxValue
        {
            get { return textBox1.Text; }
            set { textBox1.Text = value; }
        }

        public Form2(string value) {
            InitializeComponent();
            TextBoxValue = value;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            this.DialogResult = DialogResult.OK;
        }

    }
}

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 WindowsFormsApplication3
{
    public partial class Form2 : Form
    {
        public Form2():this(null)
        {
            
        }

        public string TextBoxValue
        {
            get { return textBox1.Text; }
            set { textBox1.Text = value; }
        }

        public Form2(string value) {
            InitializeComponent();
            TextBoxValue = value;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            this.DialogResult = DialogResult.OK;
        }
       
    }
}

这是传值方式是最基本，租常见的一种，还有一种方式，就是打开子窗体Form2后，在往Form2上的控件上输入值的时候，Form1上的控件上的值也跟着变化，

对于这种情况，问你就需要使用 事件委托来完成。

----------------------------------------------------------快乐的分割线-------------------------------------------------------------

Form1代码：

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 WindowsFormsApplication3
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button2_Click(object sender, EventArgs e)
        {
            Form2 f2 = new Form2();
            f2.TextBoxChanged += new EventHandler(
                (sender1, e1) =>
                { textBox2.Text = f2.TextBoxValue; }
            );
            f2.FormClosed += new FormClosedEventHandler(
                (sender2, e2) => { f2 = null; }
            );
            f2.Show(this);
        }
    }
}

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 WindowsFormsApplication3
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        
        private void button2_Click(object sender, EventArgs e)
        {
            Form2 f2 = new Form2();
            f2.TextBoxChanged += new EventHandler(
                (sender1, e1) =>
                { textBox2.Text = f2.TextBoxValue; }
            );
            f2.FormClosed += new FormClosedEventHandler(
                (sender2, e2) => { f2 = null; }
            );
            f2.Show(this);
        }
    }
}

Form2代码：

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 WindowsFormsApplication3
{
    public partial class Form2 : Form
    {
        public Form2():this(null)
        {

        }

        public string TextBoxValue
        {
            get { return textBox1.Text; }
            set { textBox1.Text = value; }
        }

        public event EventHandler TextBoxChanged;

        public Form2(string value) {
            InitializeComponent();
            TextBoxValue = value;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            this.DialogResult = DialogResult.OK;
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {
            if (TextBoxChanged != null)
            {
                TextBoxChanged(this, e);
            }
        }
    }
}

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 WindowsFormsApplication3
{
    public partial class Form2 : Form
    {
        public Form2():this(null)
        {
            
        }

        public string TextBoxValue
        {
            get { return textBox1.Text; }
            set { textBox1.Text = value; }
        }

        public event EventHandler TextBoxChanged;

        public Form2(string value) {
            InitializeComponent();
            TextBoxValue = value;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            this.DialogResult = DialogResult.OK;
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {
            if (TextBoxChanged != null)
            {
                TextBoxChanged(this, e);
            }
        }
    }
}

这里需要使用 TextBox的TextChanged事件。

上面就是两种子窗体传入父窗体值的方法。