WinForm 窗体间的传值

     父窗口:  

      private string strValueA = "";
        public string StrValueA
        {
            get
            {
                return this.strValueA;
            }
            set
            {
                this.strValueA = value;
            }
        }
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            this.strValueA = this.textBox1.Text;
            Form2 frmchild = new Form2();
            frmchild.Owner = this;
            frmchild.ShowDialog();
        }

        private void button2_Click(object sender, EventArgs e)
        {
            this.strValueA = this.textBox1.Text;
            Form2 frmchild = new Form2(this.textBox1.Text);
            frmchild.Owner = this;
            string returnValue = "";
            if (frmchild.ShowDialog() == DialogResult.OK)
            {
                // 获取子窗口传回的属性值
                returnValue = frmchild.Str;
                this.textBox1.Text = returnValue;
            }
        }

     子窗口:

// 设置它的变量和属性
        private string str;
        public string Str
        {
            get
            {
                return this.str;
            }
            set
            {
                this.str = value;
            }
        }
        // 定义一个父窗口对象
        private Form1 frmparent;

        // 默认构造函数
        public Form2()
        {
            InitializeComponent();
        }
        // 构造函数
        public Form2(string str)
        {
            this.str = str;
            InitializeComponent();
            // 赋文本框为传入的值
            this.textBox1.Text = str;
        }

        private void Form2_Load(object sender, EventArgs e)
        {
            // 将定义的父窗口对象赋值为子窗口所指向的父窗口
            frmparent = (Form1)this.Owner;
            // 同时在文本框中显示父窗口的属性值
            this.textBox1.Text = frmparent.StrValueA;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            this.Str = this.textBox1.Text;
            this.DialogResult = DialogResult.OK;
            // 从子窗口中传数值给父窗口
            // this.Str = "hello";
            this.Close();
        }