Bool 类型变量的使用

定义一个bool类型的变量，默认为FALSE的

 private bool BHaveBeenTip=false;
 private void label5_Click(object sender, EventArgs e)
         {
             var oFileBrowser = new FileBowser();
             if (oFileBrowser.ShowDialog() == DialogResult.OK)
             {
                 foreach (string fName in oFileBrowser.ListSelectedFile)
                 {
                         this.AddAttachment(fName, false, false);
                 }
                 bHasBeenTips = false;
             }
             oFileBrowser.Dispose();
         }

 private void AddAttachment(string aFileName, bool aIsDelete, bool aIsLargeAttachment)
 {
             if (attachList.Exists(o => o.Equals(aFileName, StringComparison.OrdinalIgnoreCase)))
             {
                      if (!bHasBeenTips)     //此处省略了  if(!bHasBeenTips==true)
                     {
                 MessageBoxEx.ShowBox("不允许上传同名文件.", MessageBoxButtons.OK);
                 bHasBeenTips = true;
 }
                 return;
             }
             else
             {
                     ..................................
              }
 }