[英]Simple Calculator Application in C#
关于这个我要在C#中构建的简单计算器应用程序,我有两个快速问题。 (顺便说一下,这不是家庭作业)我试图让MessageBox.Show消息显示在代码的乘法和加法部分中,但是即使我输入了负值,它们也似乎没有显示。 该应用程序似乎仍然可以进行数学计算。 另外,这可能是一个愚蠢的问题,如何摆脱应用程序中出现的label5文本,而又不删除其在属性窗口中的内容?
任何帮助将不胜感激,谢谢!
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 AddMultiply
{
public partial class AddMultiply : Form
{
public AddMultiply()
{
InitializeComponent();
}
private void label1_Click(object sender, EventArgs e)
{
}
private void txtFirstValue_TextChanged(object sender, EventArgs e)
{
}
private void btnAdd_Click(object sender, EventArgs e)
{
double firstValue;
double secondValue;
double answer;
while (double.TryParse(txtFirstValue.Text, out firstValue) == false)
{
MessageBox.Show("The value(s) entered must be > 0");
}
while(double.TryParse(txtSecondValue.Text, out secondValue) == false)
{
MessageBox.Show("The value(s) entered must be > 0");
}
answer = firstValue + secondValue;
lblAnswer.Text = answer.ToString();
}
private void btnMultiply_Click(object sender, EventArgs e)
{
double firstValue;
double secondValue;
double answer;
while (double.TryParse(txtFirstValue.Text, out firstValue) == false)
{
MessageBox.Show("The value(s) entered must be > 0");
}
while (double.TryParse(txtSecondValue.Text, out secondValue) == false)
{
MessageBox.Show("The value(s) entered must be > 0");
}
answer = firstValue * secondValue;
lblAnswer.Text = answer.ToString();
}
private void lblAnswer_Click(object sender, EventArgs e)
{
lblAnswer.Text = ""; //tries to get rid of "label5" text in application, but fails to do so
}
}
}
1)您应将while更改为“ if”:
私有无效btnAdd_Click(object sender,EventArgs e){double firstValue; double secondValue; 双重答案;
if (double.TryParse(txtFirstValue.Text, out firstValue) == false)
{
MessageBox.Show("The value(s) entered must be > 0");
}
if(double.TryParse(txtSecondValue.Text, out secondValue) == false)
{
MessageBox.Show("The value(s) entered must be > 0");
}
answer = firstValue + secondValue;
lblAnswer.Text = answer.ToString();
}
2)Ladel5在哪里? 它似乎不存在...
您可以尝试以下代码来显示MessageBox,然后该值小于0:
if (n1 < 0 || n2 < 0)
MessageBox.Show("Value less than ZERO ", "Value less than ZERO",MessageBoxButtons.OK , MessageBoxIcon.Exclamation);
至于摆脱标签,您可以尝试:
label5.Visible = false;
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