Question

我有一个表单，我需要在组合框中提取项目列表，并将查询作为参数。在数据库中，我有三个字段用于开发，网络融资等位置，根据复选框上的勾选存储为是或否。如果公司有开发仓位，则勾选的值为dB，否则为no.so on一个表单我试图在组合框中加载有可用职位的公司的名称。并且我试图从一个组合框中为dev，net，fin作为项目的位置这样做，所以如果选择dev，那么查询应该查找具有dev位置为yes的公司，读者应该阅读它并显示它在组合框中。对此有任何帮助.....这是我的代码....提前感谢。

 Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
    If ComboBox3.Text = "Developer" Then
        Dim dbprovider As String = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Users\Taher\Documents\Visual Studio 2010\Projects\WindowsApplication1\WindowsApplication1\Database1.accdb;Persist Security Info=False;"
        Me.con = New OleDb.OleDbConnection
        Dim sqlquery As String = "SELECT cname FROM company WHERE dev='"yes"';"
        Dim command As New OleDb.OleDbCommand(sqlquery, con)
        Dim reader As OleDb.OleDbDataReader
        con.ConnectionString = dbprovider
        con.Open()

        reader = command.ExecuteNonQuery()
        reader.Read()

        ComboBox3.SelectedItem.ToString()

    End If
End Sub

Answer 1

 public static List<string> GetAllExpenseType()
        {
            List<string> listExpenseType= new List<string>();
            SqlCommand command= null;
            try
            {
                command = new SqlCommand("select expname from Hm_ExpType", DbConnection.OpenConnection());

                SqlDataReader reader = command.ExecuteReader();

                while (reader.Read())
                {
                    listExpenseType.Add(reader[0].ToString());
                }

                reader.Close();
                DbConnection.CloseConnection(command.Connection);

                return listExpenseType;

            }
            catch (Exception exp)
            {
                throw exp;
            }

            finally { DbConnection.CloseConnection(command.Connection); }

            return listExpenseType;
        }




List<string> listexpType = ExpenseBO.GetAllExpenseType();
 comboExpType.DataSource = listexpType;

如何使用组合框在vb.net中的组合框中加载列表

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