C# List去重复（提取一张表中某个属性的所有值并去重复）and 过滤string字符串

 BuyRecords=List<model>();//BuyRecords是list表

List<string> Shop_name = BuyRecords.Select(e => e.ddm_id).Distinct().ToList();

 

 

//过滤string字符串

if (!string.IsNullOrEmpty(data.ddm) && data.ddm != "") //门店代码非空
{
if (data.ddm.Contains(","))
{
string[] ddms = data.ddm.Split(',');
string csddm = "";
for (int i = 0; i < ddms.Length; i++)
{
if (i == 0)
{
csddm += "'" + ddms[i] + "'";
}
else
{
csddm += ",'" + ddms[i] + "'";
}
}
sql += " and ddm_id in (" + csddm + ") ";
}
else
{
sql += " and ddm_id=@ddm ";
}
}