c# 中的default

C# 中 使用变量有时候 会把变量定义和初始化赋值分开

 

当赋值出错时，需要判断 。

如

                        DateTime dateA= default(DateTime);
                         
                        try
                        {                  
                            dateA = DateTime.Parse(fieldValueA);

                             // .....其他程序
                           
                        }
                        catch
                        {
                            if (dateA == default(DateTime)) 

                            {
                                //dateA 时赋值失败

                             }

                          }