c# - decimal.Parse 无法在 visual studio 2012 中使用

Question

首先，我希望我不会因为再次发布相同的问题而踩到任何脚趾。昨天我发布了一个问题 ( https://stackoverflow.com/questions/20734071/trouble-when-using-parse )，该问题被搁置了，因为我认为我不清楚。

现在我一直在做一些菜鸟研究，.Parse 问题似乎只在我使用 decimal.Parse 时出现。例如，这很好用:

private void button1_Click(object sender, EventArgs e)
        {
            string text = "500";
            int num = int.Parse(text);
            MessageBox.Show(num.ToString());
        }

但是这个:

private void button1_Click(object sender, EventArgs e)
        {

            decimal text = decimal.Parse(textBox1.Text);
            decimal total = text * 2;
            MessageBox.Show(total.ToString());

        }

导致此错误: (textBox1 中的值为 10.00)

我已尝试重新安装 Visual Studio，但问题仍然存在。

编辑:

System.FormatException was unhandled
  HResult=-2146233033
  Message=Input string was not in a correct format.
  Source=mscorlib
  StackTrace:
       at System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal)
       at System.Number.ParseDecimal(String value, NumberStyles options, NumberFormatInfo numfmt)
       at System.Decimal.Parse(String s)
       at WindowsFormsApplication4.Form1.button1_Click(Object sender, EventArgs e) in c:\Users\XXX\Documents\Visual Studio 2012\Projects\WindowsFormsApplication4\Form1.cs:line 23
       at System.Windows.Forms.Control.OnClick(EventArgs e)
       at System.Windows.Forms.Button.OnClick(EventArgs e)
       at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
       at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
       at System.Windows.Forms.Control.WndProc(Message& m)
       at System.Windows.Forms.ButtonBase.WndProc(Message& m)
       at System.Windows.Forms.Button.WndProc(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
       at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
       at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
       at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.Run(Form mainForm)
       at WindowsFormsApplication4.Program.Main() in c:\Users\XXX\Documents\Visual Studio 2012\Projects\WindowsFormsApplication4\Program.cs:line 19
       at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException: 

Answer 1

由于您实际上传递的是一个包含数字的字符串，我认为这是文化问题。以下是一些提示:

• 在 Parse 方法的不同重载中指定一个 NumberStyles
• 在 Parse 方法的不同重载中指定不变文化
• 同时指定

请看下面的例子:

decimal text = decimal.Parse(textBox1.Text, NumberStyles.Any, CultureInfo.InvariantCulture);

还有一个与您的问题没有直接关系的提示...始终使用 TryParse 使转换更安全