#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 WindowsFormsApplication1

{

public partial class Form1 : Form

    {

          public Form1()

           {

                InitializeComponent();

}

private void textBox1_TextChanged(object sender, EventArgs e)

{

}

private void button1_Click(object sender, EventArgs e)

{

float num1 = 0;

float num2 = 0;

float result = 0;

num1 = float.Parse(textBox1.Text); //将文本框输入的字符转换成数值

num2 = float.Parse(textBox2.Text);

result = num1 * num2;

textBox3.Text = result.ToString(); //将数值转换成字符

}

private void button2_Click(object sender, EventArgs e)

{

textBox1.Text = "";

textBox2.Text = "";

textBox3.Text = "";

        }

     }

}

#效果