c＃桌面应用程序中不允许使用默认参数说明符

Question

private string formatSizeBinary(Int64 size, Int32 decimals = 2)
        {
            string[] sizes = { "Bytes", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB" };
            double formattedSize = size;
            Int32 sizeIndex = 0;
            while (formattedSize >= 1024 & sizeIndex < sizes.Length)
            {
                formattedSize /= 1024;
                sizeIndex += 1;
            }
            return string.Format("{0} {1}", Math.Round(formattedSize, decimals).ToString(), sizes[sizeIndex]);
        }

我得到了这个

  

“不允许使用默认参数说明符”

"Int32 decimals = 2"

上的

错误

Answer 1

由于您的代码对我来说很好，但Optional parameters附带Visual Studio 2010（可能还有.NET 4.0框架）

  

Visual C＃2010引入了命名和可选参数

您需要一个类似的方法

private string formatSizeBinary(Int64 size, Int32 decimals, int value)
        {
            decimals = value;
            string[] sizes = { "Bytes", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB" };
            double formattedSize = size;
            Int32 sizeIndex = 0;
            while (formattedSize >= 1024 & sizeIndex < sizes.Length)
            {
                formattedSize /= 1024;
                sizeIndex += 1;
            }
            return string.Format("{0} {1}", Math.Round(formattedSize, decimals).ToString(), sizes[sizeIndex]);
        }

然后你可以称它为你想要的值;

formatSizeBinary(yoursize, decimals, 2);
formatSizeBinary(yoursize, decimals, 3);
formatSizeBinary(yoursize, decimals, 4);