[keyword] 預設關係字default(T) 輸出結果匯總
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: }
同理可證 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: }
