小编Osa*_*ama的帖子

标题说明了一切.我有一个充当白板的面板.在鼠标移动时绘制鼠标轨道..工作正常,但如果鼠标离开面板的边缘,我想调用鼠标向上事件和鼠标按下事件如果鼠标离开或进入面板而单击左按钮

 private void panel2_MouseLeave(object sender, EventArgs e)
    {
        if (mousedraw == true)
        {
            panel2_MouseUp(sender, new MouseEventArgs(System.Windows.Forms.MouseButtons.Left, 0, MousePosition.X, MousePosition.Y, 0));
        }
    }

    private void panel2_MouseEnter(object sender, EventArgs e)
    {
        if (mousedraw == true)
        {
            panel2_MouseDown(sender, new MouseEventArgs(System.Windows.Forms.MouseButtons.Left, 0, MousePosition.X, MousePosition.Y, 0));
        }
    }

mousedraw是一个bool,知道是否单击了左键.

该问题是:

如果鼠标按钮关闭,则不会触发leave和enter事件.

我有 2 个类（实体）Exemption 和 Period，我想使用来自豁免的 IdNumber 和来自 Period 的 Id 创建一个唯一索引

     public class Exemption
        {
            [Key]
            public int Id { get; set; }
            [Required]
            public string FirstName { get; set; }
            .
            .
            .
            [Required]
            public string IdNumber { get; set; }
            [Required]
            public Period Period { get; set; }
         }

     public class Period
        {
            [Key]
            public int Id { get; set; }
            .
            .
            .
            [Required]
            public string Year { get; set; }

         }

使用 Fluent API 我在OnModelCreating …

我试图格式化string使用string.Format但它抛出异常.

 var format = "public {0} {1} { get; {2}set; }";
        var arg0 = "long";
        var arg1 = "Ticks";

        var formatedString = string.Format(format, arg0, arg1, null);

最后一行抛出一个System.FormatException具有以下细节:

    System.FormatException was unhandled
  HResult=-2146233033
  Message=Input string was not in a correct format.
  Source=mscorlib
  StackTrace:
       at System.Text.StringBuilder.AppendFormatHelper(IFormatProvider provider, String format, ParamsArray args)
       at System.String.FormatHelper(IFormatProvider provider, String format, ParamsArray args)
       at System.String.Format(String format, Object arg0, Object arg1, Object arg2)
       at ConsoleApplication1.Program.Main(String[] args) in E:\lab\cheque\helloworldprism\ConsoleApplication1\ConsoleApplication1\Program.cs:line 11
       at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] …