Tips: Visual Studio 設定除錯中斷點 1

通常在Visual Studio設中斷點只要在左側灰色地方點一下即可,例如:

不過,在for迴圈的情況下,只會在 int i=0此行設定中斷點
若要在i<100這行設中斷點,可以將游標停留在此行,按f9,如:> 即可設好中斷點

C# 4 Covariant & Contravariant

C#4封閉的泛型支援Covariant & Contravariant,例如以下程式在C# 3不可編譯;在C# 4可正常執行

1 class outputsafe

2 {

3 static void Main(string[] args)

4 {

5 IEnumerable<string> data = new string[] { "a", "b" };

6 PrintData(data);

7 }

8 public static void PrintData(IEnumerable<object> o)

9 {

10 foreach (var t in o)

11 {

12 Console.WriteLine(t);

13 }

14 }

15 }

VB 10 的新語法

1.Auto-Implemented Properties 自動實作屬性

1 Module Module1

2 Property EmpName As String = "Mary"

3 Sub Main()

4 Console.WriteLine(EmpName)

5 End Sub

6 End Module

2.Collection Initializers & Statement Lambdas ,
除了3.5的Array Initializer之外,多了Collection Initializers

1 Module Module1

2 Sub Main()

3 '陣列初始設定式

4 Dim dataArr() As Integer = {1, 4, 23, 21, 34, 24}

5 Array.ForEach(dataArr, Sub(x)

6 Console.WriteLine(x)

7 End Sub)

8

9 '集合初始設定式

10 Dim dataCol As New List(Of Integer) From {1, 4, 23, 21, 34, 24}

11 dataCol.ForEach(Sub(x)

12 Console.WriteLine(x)

13 End Sub)

14 End Sub

15 End Module

C# 4 具名參數

參數可以命名,例如:

1 class Program

2 {

3 static void Main(string[] args) {

4 Console.WriteLine(Add(x:20,y:10));

5 }

6 static int Add(int x, int y)

7 {

8 return x + y;

9 }

10 }

C# 4 選擇性引數(Optional Arguments)

宣告方法的引數,給個預設值就行了,例如:

1 class Program {

2 static void Main(string[] args) {

3 Console.WriteLine(Add(10, 20));

4 Console.WriteLine(Add(10, 20,30));

5 }

6 static int Add(int x, int y, int z = 0) {

7 return x + y + z;

8 }

9 }