父窗体与子窗体传递问题

最新推荐文章于 2024-05-18 22:58:05 发布

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最新推荐文章于 2024-05-18 22:58:05 发布

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分类专栏： C#知识点滴文章标签： textbox exception class object button string

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需求：父窗体一TextBox点击后弹出子窗体，在子窗体中数值计算后返回结果给父窗体中的TextBox.

设计：

1、父窗体：一TextBox控件

2、子窗体：两个TextBox控件，分别用于接受两个数值；一个Combobox控件用于选中运算符，一Lable控件；一Button控件，取结果返回并关闭子窗体。

实现：

1、Program.cs

namespace CalculateForWhat
{
    static class Program
    {
        /// <summary>
        /// 应用程序的主入口点。
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form1());
            //Application.Run(new Form2());
        }
    }
}

2、Form1父窗体：

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

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

        private void txtbox_ReceiveVal_Click(object sender, EventArgs e)
        {
            Form2 f = new Form2(this);//注意将当前父窗体实例传递到Form2
            f.Show();
        }
    }
}

3、Form2子窗体

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

namespace CalculateForWhat
{
    public partial class Form2 : Form
    {
        Form1 _frm1;
        public Form2(Form1 frm1)
        {
            InitializeComponent();
            this.BindCombobox();

this._frm1 = frm1;//接受父窗体实例，这样就可用_frm1调用父窗体控件
}

        private void BindCombobox()
        {
            //throw new Exception("The method or operation is not implemented.");
            ArrayList al = new ArrayList();
            al.Add("+");
            al.Add("-");
            al.Add("*");
            al.Add("/");
            this.comboBox1.DataSource = al;

}

        private void btn_GetVal_Click(object sender, EventArgs e)
        {
            double val1, val2;
            double finalVal;
            try
            {
                val1 = Convert.ToDouble(this.textBox1.Text.Trim());
                val2 = Convert.ToDouble(this.textBox2.Text.Trim());
            }
            catch
            {
                MessageBox.Show("请在文本框中输入数值！！", "出错啦", MessageBoxButtons.OK);
                return;
            }

            string flag = this.comboBox1.SelectedValue.ToString();
            switch (flag)
            {
                case "+":
                    finalVal = val1 + val2;
                    break;

                case "-":
                    finalVal = val1 - val2;
                    break;

                case "*":
                    finalVal = val1 * val2;
                    break;

                case "/":
                    finalVal = val1 / val2;
                    break;
                default: throw new Exception("错误的运算符！！");
                    break;
            }
            this._frm1.txtbox_ReceiveVal.Text = finalVal.ToString();//Success

this.Close();//关闭当前窗体

}

--------------------------------------------

END

}
}