从AutoCompleteStringCollection中删除重复项c＃

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。 和combobox从treatmentCollection类的AutoCompleteStringCollection对象获取值 请帮帮我？

Answer 1

替换：

select Treatment from NewPatient

到此：

select distinct Treatment from NewPatient

Answer 2

如果只想要不同的值，可以在sql命令中使用DISTINCT，如;

select DISTINCT Treatment from NewPatient

查看Eliminating Duplicates with DISTINCT

Answer 3

我使用此代码并且工作正常。

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