如果您使用的是 EntityFramework
//resultset is the result from the query that return all data
var duplicates = resultset
.GroupBy(i => i.ColumnName)
.Where(x => x.Count() > 1)
.Select();
如果使用数据表
DataTable dt = new DataTable();
dt.Columns.Add("Id", typeof(int));
dt.Columns.Add("Name", typeof(string));
dt.Columns.Add("City", typeof(string));
//populate table
dt.Rows.Add(1, "David", "New York");
dt.Rows.Add(2, "Emma","Albany");
dt.Rows.Add(3, "Michael", "Chicago");
dt.Rows.Add(4, "Jennifer", "Chicago");
dt.Rows.Add(5, "Steve", "Albany");
var duplicates = dt.AsEnumerable()
.GroupBy(r => r.Field<string>("City"))
.Select(g => g.First())
.CopyToDataTable();
重复项将具有唯一的重复行