我有一个数据表：
DataTable table = new DataTable();
DataColumn column;
column = new DataColumn();
column.DataType = Type.GetType("System.String");
column.ColumnName = "RelationshipTypeDescription";
table.Columns.Add(column);
column = new DataColumn();
column.DataType = Type.GetType("System.String");
column.ColumnName = "RelatedContactName";
table.Columns.Add(column);
我想知道DISTINCT COUNT OF COLUMN“RelationshipTypeDescription”.
我不确定如何在这里引用列名：
int relationshipCount = table.AsEnumerable().Distinct().Count();
有人可以帮我一把吗？
解决方法
你可以这样做：
int relationshipCount = table
.AsEnumerable()
.Select(r => r.Field<string>("RelationshipTypeDescription"))
.Distinct()
.Count();
但是你可能不需要调用AsEnumerable：
int relationshipCount = table
.Select(r => r.Field<string>("RelationshipTypeDescription")) // Compiler error: "Cannot convert lambda expression to type 'string' because it is not a delegate type"
.Distinct()
.Count();