將數組作為參數傳遞（C# 編程指南） · MSDN C# 編程指南 & 參考手冊 2015

# 將數組作為參數傳遞（C# 編程指南）數組可作為實參傳遞給方法形參。由于數組是引用類型，因此方法可以更改元素的值。 ## 將一維數組作為參數傳遞可以將初始化的一維數組傳遞給方法。例如，下面的語句將數組發送到 print 方法。 ``` int[] theArray = { 1, 3, 5, 7, 9 }; PrintArray(theArray); ``` 下面的代碼顯示 print 方法的部分實現。 ``` void PrintArray(int[] arr) { // Method code. } ``` 您可以在一個步驟中初始化和傳遞新數組，如下面的示例所示。 ``` PrintArray(new int[] { 1, 3, 5, 7, 9 }); ``` ## 示例 ### 說明在下面的示例中，將初始化一個字符串數組并將其作為參數傳遞到字符串的 PrintArray 方法。該方法顯示數組的元素。接下來，調用 ChangeArray 和 ChangeArrayElement 方法以演示通過值發送數組參數時不會阻止更改這些數組元素。 ### 代碼 ``` class ArrayClass { static void PrintArray(string[] arr) { for (int i = 0; i < arr.Length; i++) { System.Console.Write(arr[i] + "{0}", i < arr.Length - 1 ? " " : ""); } System.Console.WriteLine(); } static void ChangeArray(string[] arr) { // The following attempt to reverse the array does not persist when // the method returns, because arr is a value parameter. arr = (arr.Reverse()).ToArray(); // The following statement displays Sat as the first element in the array. System.Console.WriteLine("arr[0] is {0} in ChangeArray.", arr[0]); } static void ChangeArrayElements(string[] arr) { // The following assignments change the value of individual array // elements. arr[0] = "Sat"; arr[1] = "Fri"; arr[2] = "Thu"; // The following statement again displays Sat as the first element // in the array arr, inside the called method. System.Console.WriteLine("arr[0] is {0} in ChangeArrayElements.", arr[0]); } static void Main() { // Declare and initialize an array. string[] weekDays = { "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" }; // Pass the array as an argument to PrintArray. PrintArray(weekDays); // ChangeArray tries to change the array by assigning something new // to the array in the method. ChangeArray(weekDays); // Print the array again, to verify that it has not been changed. System.Console.WriteLine("Array weekDays after the call to ChangeArray:"); PrintArray(weekDays); System.Console.WriteLine(); // ChangeArrayElements assigns new values to individual array // elements. ChangeArrayElements(weekDays); // The changes to individual elements persist after the method returns. // Print the array, to verify that it has been changed. System.Console.WriteLine("Array weekDays after the call to ChangeArrayElements:"); PrintArray(weekDays); } } // Output: // Sun Mon Tue Wed Thu Fri Sat // arr[0] is Sat in ChangeArray. // Array weekDays after the call to ChangeArray: // Sun Mon Tue Wed Thu Fri Sat // // arr[0] is Sat in ChangeArrayElements. // Array weekDays after the call to ChangeArrayElements: // Sat Fri Thu Wed Thu Fri Sat ``` ## 將多維數組作為參數傳遞可采用與傳遞一維數組相同的方式將初始化的多維數組傳遞給方法。 ``` int[,] theArray = { { 1, 2 }, { 2, 3 }, { 3, 4 } }; Print2DArray(theArray); ``` 下面的代碼顯示 print 方法的部分聲明，該方法接受一個二維數組作為其參數。 ``` void Print2DArray(int[,] arr) { // Method code. } ``` 您可以在一個步驟中初始化和傳遞新數組，如下面的示例所示。 ``` Print2DArray(new int[,] { { 1, 2 }, { 3, 4 }, { 5, 6 }, { 7, 8 } }); ``` ## 示例 ### 說明在下面的示例中，將初始化一個二維整數數組并將其傳遞到 Print2DArray 方法。該方法顯示數組的元素。 ### 代碼 ``` class ArrayClass2D { static void Print2DArray(int[,] arr) { // Display the array elements. for (int i = 0; i < arr.GetLength(0); i++) { for (int j = 0; j < arr.GetLength(1); j++) { System.Console.WriteLine("Element({0},{1})={2}", i, j, arr[i, j]); } } } static void Main() { // Pass the array as an argument. Print2DArray(new int[,] { { 1, 2 }, { 3, 4 }, { 5, 6 }, { 7, 8 } }); // Keep the console window open in debug mode. System.Console.WriteLine("Press any key to exit."); System.Console.ReadKey(); } } /* Output: Element(0,0)=1 Element(0,1)=2 Element(1,0)=3 Element(1,1)=4 Element(2,0)=5 Element(2,1)=6 Element(3,0)=7 Element(3,1)=8 */ ``` ## 請參閱 [C# 編程指南](https://msdn.microsoft.com/zh-cn/library/67ef8sbd.aspx) [數組（C# 編程指南）](https://msdn.microsoft.com/zh-cn/library/9b9dty7d.aspx) [一維數組（C# 編程指南）](https://msdn.microsoft.com/zh-cn/library/0a7fscd0.aspx) [多維數組（C# 編程指南）](https://msdn.microsoft.com/zh-cn/library/2yd9wwz4.aspx) [交錯數組（C# 編程指南）](https://msdn.microsoft.com/zh-cn/library/2s05feca.aspx)