将数组作为参数传递（C# 编程指南） · MSDN C# 编程指南 & 参考手册 2015

# 将数组作为参数传递（C# 编程指南）数组可作为实参传递给方法形参。由于数组是引用类型，因此方法可以更改元素的值。 ## 将一维数组作为参数传递可以将初始化的一维数组传递给方法。例如，下面的语句将数组发送到 print 方法。 ``` int[] theArray = { 1, 3, 5, 7, 9 }; PrintArray(theArray); ``` 下面的代码显示 print 方法的部分实现。 ``` void PrintArray(int[] arr) { // Method code. } ``` 您可以在一个步骤中初始化和传递新数组，如下面的示例所示。 ``` PrintArray(new int[] { 1, 3, 5, 7, 9 }); ``` ## 示例 ### 说明在下面的示例中，将初始化一个字符串数组并将其作为参数传递到字符串的 PrintArray 方法。该方法显示数组的元素。接下来，调用 ChangeArray 和 ChangeArrayElement 方法以演示通过值发送数组参数时不会阻止更改这些数组元素。 ### 代码 ``` 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 ``` ## 将多维数组作为参数传递可采用与传递一维数组相同的方式将初始化的多维数组传递给方法。 ``` int[,] theArray = { { 1, 2 }, { 2, 3 }, { 3, 4 } }; Print2DArray(theArray); ``` 下面的代码显示 print 方法的部分声明，该方法接受一个二维数组作为其参数。 ``` void Print2DArray(int[,] arr) { // Method code. } ``` 您可以在一个步骤中初始化和传递新数组，如下面的示例所示。 ``` Print2DArray(new int[,] { { 1, 2 }, { 3, 4 }, { 5, 6 }, { 7, 8 } }); ``` ## 示例 ### 说明在下面的示例中，将初始化一个二维整数数组并将其传递到 Print2DArray 方法。该方法显示数组的元素。 ### 代码 ``` 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 */ ``` ## 请参阅 [C# 编程指南](https://msdn.microsoft.com/zh-cn/library/67ef8sbd.aspx) [数组（C# 编程指南）](https://msdn.microsoft.com/zh-cn/library/9b9dty7d.aspx) [一维数组（C# 编程指南）](https://msdn.microsoft.com/zh-cn/library/0a7fscd0.aspx) [多维数组（C# 编程指南）](https://msdn.microsoft.com/zh-cn/library/2yd9wwz4.aspx) [交错数组（C# 编程指南）](https://msdn.microsoft.com/zh-cn/library/2s05feca.aspx)