c# - 从 AutoCompleteStringCollection c# 中删除重复项

Question

AutoCompleteStringCollection treatmentCollection = new AutoCompleteStringCollection();
if (con.State == ConnectionState.Closed)
{
    con.Open();
}
SqlCeCommand cmdTreatment = new SqlCeCommand("select Treatment from NewPatient", con);
SqlCeDataReader readerTreatment = cmdTreatment.ExecuteReader();
if (readerTreatment.Read() == true)
{
    while (readerTreatment.Read())
    {
        treatmentCollection.Add(readerTreatment["Treatment"].ToString());
    }
}
comboBox2.AutoCompleteMode = AutoCompleteMode.Suggest;
comboBox2.AutoCompleteSource = AutoCompleteSource.CustomSource;
comboBox2.AutoCompleteCustomSource = treatmentCollection;
if (con.State == ConnectionState.Open)
{
    con.Close();
}

我希望combobox2应该只有不同的价值。treatmentCollection并且组合框从类对象中获取价值AutoCompleteStringCollection请帮助我？

Answer 1

代替：

select Treatment from NewPatient

对此：

select distinct Treatment from NewPatient

Answer 2

如果你只想要不同的值，你可以DISTINCT在你的 sql 命令中使用，比如；

select DISTINCT Treatment from NewPatient

查看Eliminating Duplicates with DISTINCT

Answer 3

我使用使用此代码，它工作正常。

string query = @"Select distinct [FieldName] from [tableName]";