Question

我目前正在使用Visual Studio中的Windows窗体进行第一次作业，并且有点卡住了。

我正在尝试测试用户输入是否为数字，如果输入不是数字，则弹出一个小消息框并提醒用户。（我已完成此部分）。我遇到的问题是在Visual Studio中继续出现错误

error

这是格式化问题吗？我应该重新格式化我的代码吗？你可能会看到我是C＃（和编程）的新手。

我的代码：

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 wtgCalculator {
public partial class Form1 : Form {

   const double maleratio = 0.536;
   const double femaleratio = 0.492;


    public Form1() {

        InitializeComponent();
    }

    private void textBox1_TextChanged(object sender, EventArgs e) {

    }

    private void Form1_Load(object sender, EventArgs e) {

    }

    private void label1_Click(object sender, EventArgs e) {

    }

    private void textBox1_TextChanged_1(object sender, EventArgs e) {

    }

    private void WaistNumericCheck() {

        double waist;
        string inpwaist = heighttextbox.Text;

        if (double.TryParse(inpwaist, out waist)) {

            MessageBox.Show("Value must be numeric");      //this is where the problem is



        }                                    
    }

    private void HeightNumericCheck() {          
        //todo
    }

    private void button1_Click(object sender, EventArgs e) {

        //record inputs to variables
        WaistNumericCheck();
        HeightNumericCheck();
        double height = double.Parse(heighttextbox.Text);
        double waist = double.Parse(waisttextbox.Text);             
        //check is inputs are within boundry          
        CheckDimensions(height, waist);
        //test
       // ShowResult(height, waist);               

    }


    private void CheckLimits(double height, double waist) {

        double result = CalculateRatio(height, waist);

        if (Female.Checked) {

            if (result < femaleratio) {

                MessageBox.Show("Your risk of obesity related cardiovasular is low");

            }

            if (result > femaleratio) {

                MessageBox.Show("Your risk of obesity related to cardiovascular is high");

            }

        }

        if (Male.Checked) {

            if (result < maleratio) {

                MessageBox.Show("Your risk of obesity related cardiovasular is low");

            }

            if (result > maleratio) {

                MessageBox.Show("Your risk of obesity related cardiovasular is High");


            }
        }


        //testing
        MessageBox.Show(result.ToString());

    }

    private void ShowResult(double height, double waist) {

        //double result = CalculateRatio(height, waist);

        //if (Female.Checked) {

        //    if (result < femaleratio) {

        //        MessageBox.Show("Your risk of obesity related cardiovasular is low");

        //    }

        //    if (result > femaleratio) {

        //        MessageBox.Show("Your risk of obesity related to cardiovascular is high");

        //    }

        //}

        //if (Male.Checked) {



        //}


    }

    private static void CheckDimensions(double height, double waist) {

        if (height <= 120) {
            MessageBox.Show("Height must be greater than 120cm");
        }

        if (waist <= 60) {
            MessageBox.Show("Waist must be greater than 60cm");
        }    
    }


    private void Gender_CheckedChanged(object sender, EventArgs e) {
        button1.Enabled = true;                        
    }

    private static double CalculateRatio(double height, double waist) {

       double finalratio = waist / height;
       return finalratio; 

    }



}
}

再次感谢，如果需要更多信息，请与我们联系。

Answer 1

你并没有真正正确地处理这个问题。如果无法转换该值，则.Parse() 假设会抛出异常。 .TryParse()的重点是避免这种情况。因此，您的方法需要进行清理和编辑才能真正实现目标：

private bool WaistNumericCheck(out double waist) 
{
    bool canParse = double.TryParse(heighttextbox.Text, out waist);

    if ( !canParse ) {
        MessageBox.Show("Value must be numeric");
    }  

    return canParse;                      
}

private bool HeightNumericCheck(out double height)
{          
    // todo -> same pattern as above
}

private void button1_Click(object sender, EventArgs e) 
{
    double height = 0, waist = 0;
    if( WaistNumericCheck(waist) && HeightNumericCheck(height) )
    {                    
        CheckDimensions(height, waist);

        /* ... the rest of your code */
    }              
}

这会根据解析是否成功修改您的测试方法以返回true / false，并且out是您的解析变量，这样您就不必再次解析它们了。

我建议您在某些时候查看MSDN文档：http://msdn.microsoft.com/en-us/library/994c0zb1%28v=vs.110%29.aspx

从C＃捕获异常并重置窗口

1 个答案: