[keyword] 默认关系字default(T) 输出结果汇总

default (C# Reference)

default Keyword in Generic Code (C# Programming Guide)

   1:          [TestMethod()]

   2:          public void DefaultTest()

   3:          {            

   4:              Assert.IsNull(default(VW_DW_EMP));

   5:  ?

   6:              Assert.IsNull(default(string));

   7:  ?

   8:              Assert.AreEqual(0, default(byte));

   9:  ?

  10:              Assert.AreEqual(0, default(int));

  11:  ?

  12:              Assert.AreEqual(0, default(long));

  13:  ?

  14:              Assert.AreEqual(0, default(float));

  15:              

  16:              Assert.AreEqual(0, default(double));

  17:  ?

  18:              Assert.AreEqual(0, default(decimal));

  19:              

  20:              Assert.AreEqual(0, default(char));

  21:  ?

  22:              Assert.AreEqual(false, default(bool));

  23:  ?

  24:              Assert.AreEqual(DateTime.MinValue, default(DateTime));

  25:  ?

  26:              Assert.AreEqual(ENUM_LAB.NONE, default(ENUM_LAB));

  27:  ?

  28:              Assert.AreEqual(new STRUCT_LAB(), default(STRUCT_LAB));

  29:  ?

  30:              Assert.IsNull(default(int?));

  31:          }

  32:  ?

  33:          enum ENUM_LAB

  34:          {

  35:              NONE, UT01, UT02

  36:          }

  37:  ?

  38:          struct STRUCT_LAB

  39:          {

  40:              string UT;

  41:          }

同理可证 LINQ :

   1:          [TestMethod()]

   2:          public void LinqDefaultTest()

   3:          {

   4:              int[] intArray = { };

   5:              Assert.AreEqual(0, intArray.FirstOrDefault());

   6:  ?

   7:              string[] strArray = { };

   8:              Assert.IsNull(strArray.FirstOrDefault());

   9:  ?

  10:              VW_DW_EMP[] empArray = { };

  11:              Assert.IsNull(empArray.FirstOrDefault());

  12:  ?

  13:              bool[] boolArray = { };

  14:              Assert.AreEqual(false, boolArray.FirstOrDefault());

  15:  ?

  16:              bool?[] nullableBoolArray = { };

  17:              Assert.IsNull(nullableBoolArray.FirstOrDefault());

  18:  ?

  19:              DateTime[] dateTimeArray = { };

  20:              Assert.AreEqual(DateTime.MinValue, dateTimeArray.FirstOrDefault());

  21:          }

原文:大专栏  [keyword] 默认关系字default(T) 输出结果汇总

原文地址：https://www.cnblogs.com/petewell/p/11509964.html