C# list<T>去重

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收起

 

一、值类型去重

 1、List<object>

1.1 、 object is int

//object is int
            List<object> ointList = new List<object>();
            ointList.Add(1);
            ointList.Add(1);
            ointList.Add(2);
            ointList = ointList.Distinct().ToList();

 

 

1.2、 object is decimal

//object is decimal
            List<object> odecimalList = new List<object>();
            odecimalList.Add(1.25);
            odecimalList.Add(1.25);
            odecimalList.Add(2.25);
            odecimalList = odecimalList.Distinct().ToList();

 

 

1.3、 object is char

            //object is char
            List<object> ocharList = new List<object>();
            ocharList.Add('a');
            ocharList.Add('a');
            ocharList.Add('b');
            ocharList = ocharList.Distinct().ToList();

 

 

1.4、object is bool

            //object is bool
            List<object> oboolList = new List<object>();
            oboolList.Add(true);
            oboolList.Add(false);
            oboolList.Add(true);
            oboolList = oboolList.Distinct().ToList();

 

 

1.5、 object is string

            //object is string
            List<object> osList = new List<object>();
            osList.Add("1");
            osList.Add("1");
            osList.Add("2");
            osList = osList.Distinct().ToList();

 

 

2 、List<int>

            List<int> intList = new List<int>();
            intList.Add(1111);
            intList.Add(1111);
            intList.Add(2222);
            intList = intList.Distinct().ToList();

 

 

3、List<string>

 

            List<string> idList = new List<string>();
            idList.Add("1111");
            idList.Add("1111");
            idList.Add("2222");  
            idList = idList.Distinct().ToList();

 

 

二、引用类型去重

private class NetworkCtrl
        {

            #region <属性>

            /// <summary>
            /// 网控对象ID
            /// </summary>
            public string NetCtrlId { get; set; }

            /// <summary>
            /// 业务对象ID
            /// </summary>
            public string InterID { get; set; }

            /// <summary>
            /// 业务操作
            /// </summary>
            public string OperationDesc { get; set; }
            #endregion <属性>

        }

 

List<NetworkCtrl> ncList = new List<NetworkCtrl>();
            ncList.Add(new NetworkCtrl
            {
                InterID = "100148",
                NetCtrlId = "9cc2c432-56a9-b38d-11ee-794e3a9853e2",
                OperationDesc = "售后单-SH231103001-下推其它出库单"
            });
            ncList.Add(new NetworkCtrl
            {
                InterID = "100149",
                NetCtrlId = "9cc2c432-56a9-b38d-11ee-794e3a9853e2",
                OperationDesc = "售后单-SH231103002-下推其它出库单"
            });
            ncList.Add(new NetworkCtrl
            {
                InterID = "100148",
                NetCtrlId = "9cc2c432-56a9-b38d-11ee-794e3a9853e2",
                OperationDesc = "售后单-SH231103001-下推其它出库单"
            });
            var ncList1 = ncList.Distinct().ToList();
            var ncList2 = ncList.GroupBy(x => x.InterID).Select(y => y.First()).ToList();

List<NetworkCtrl> ncList = new List<NetworkCtrl>();
            ncList.Add(new NetworkCtrl
            {
                InterID = "100148",
                NetCtrlId = "9cc2c432-56a9-b38d-11ee-794e3a9853e2",
                OperationDesc = "售后单-SH231103001-下推其它出库单"
            });
            ncList.Add(new NetworkCtrl
            {
                InterID = "100149",
                NetCtrlId = "9cc2c432-56a9-b38d-11ee-794e3a9853e2",
                OperationDesc = "售后单-SH231103002-下推其它出库单"
            });
            ncList.Add(new NetworkCtrl
            {
                InterID = "100148",
                NetCtrlId = "9cc2c432-56a9-b38d-11ee-794e3a9853e2",
                OperationDesc = "售后单-SH231103001-下推其它出库单"
            });
            var ncList1 = ncList.Distinct().ToList();
            var ncList2 = ncList.GroupBy(x => x.InterID).Select(y => y.First()).ToList();

 集合里有三条记录，其中两条重复。

 

 使用Distinct后，还有三条，说明distinct失败

原因是，引用类型即使属性一样，引用地址是不一样的。
只能用别的方式去避免。