正确使用Lambda查询

Question

请考虑以下代码:

       private static void WriteProcesses(StreamWriter sw, DateTime d) {
            sw.WriteLine("List of processes @ " + d.ToString());
            Process[] localAll = Process.GetProcesses().Where(o => o.ProcessName.ToLower() != "svchost");            
            if(localAll.Length > 0) {
                for(int i = 0; i < localAll.Length; i++) {                    
                    sw.WriteLine("      " + localAll[i].ProcessName);
                }
            }
        }

但我得到一条红色的波浪线说:

无法将类型System.Collections.Generic.IEnumerable'隐式转换为'System.Diagnostics.Process []'.存在显式转换(您是否错过了演员？)

我尝试将数组更改为List但没有工作.

Answer 1

更改

Process[] localAll = Process.GetProcesses().Where(o => o.ProcessName.ToLower() != "svchost");

至

Process[] localAll = Process.GetProcesses().Where(o => o.ProcessName.ToLower() != "svchost").ToArray();

Where返回一个IEnumerable<Process>你可以调用ToArray的转换为类型的数组Process.

另外,您也可以通过枚举IEnumerable<Process>该Where返回.

var processes = Process.GetProcesses().Where(o => o.ProcessName.ToLower() != "svchost");
foreach (Process process in processes) {
    sw.WriteLine("      " + process.ProcessName);
}