VB.NET：无法显示选定的数据从访问数据库到datagridview

Question

我一直试图显示选定的数据从Access数据库到datagridview上按下按钮，但它不显示任何记录既不显示任何错误。

Dim third_da As OleDb.OleDbDataAdapter 
Dim third_ds As New DataSet 


Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click 


    con.Open() 
    Dim cb_two As New OleDb.OleDbCommandBuilder(third_da) 

    query_three = "SELECT emp_timing.emp_code, emp_timing.day, emp_timing.travel_time, emp_timing.travel_dest,emp_timing.emp_timein,emp_timing.emp_timeout, emp_timing.emp_hours, emp_timing.emp_mins " & _ 
     "FROM emp_timing WHERE (((emp_timing.emp_code)=" & empcode & ") AND ((emp_timing.day) Like '??/" & ComboBox1.Text & "/20" & TextBox9.Text & "'))" 

    ' "WHERE (((emp_timing.emp_code)=22) AND ((emp_timing.day) Like '??/05/2016'))" 

    third_da = New OleDb.OleDbDataAdapter(query_three, con) 

    third_da.Fill(third_ds, "ets") 


    DataGridView1.DataSource = third_ds.Tables("ets") 

    con.Close() 
    Dim view As New DataView(third_ds.Tables(0)) 
    source1.DataSource = view 
    DataGridView1.DataSource = view 

    DataGridView1.ReadOnly = True 
    DataGridView1.CancelEdit() 

End Sub 

在此先感谢！

Answer 1

你可以改变你emp_timing.day场的条件查询是这样的：

(Month(emp_timing.day) = & ComboBox1.Text & 
        and Year(emp_timing.day) = "20" & TextBox9.Text & ") 

不过，我建议你使用参数，以避免SQL注入，像这样：

query_three = "SELECT emp_timing.emp_code, emp_timing.day, emp_timing.travel_time, emp_timing.travel_dest,emp_timing.emp_timein,emp_timing.emp_timeout, emp_timing.emp_hours, emp_timing.emp_mins " & 
"FROM emp_timing WHERE (((emp_timing.emp_code)= @empcode) AND ((emp_timing.day) BETWEEN @startDate AND @endDate))" 

Dim startDate As New DateTime("20" & TextBox9.Text, ComboBox1.Text, 1) 
Dim endDate As DateTime = startDate.AddMonths(1).AddDays(-1) 

Dim cmd As New OleDbCommand(query_three, con) 
cmd.Parameters.AddWithValue("@empcode", empcode) 
cmd.Parameters.AddWithValue("@startDate", startDate.ToString("#yyyy/MM/dd#")) 
cmd.Parameters.AddWithValue("@endDate", endDate.ToString("#yyyy/MM/dd#")) 
third_da = New OleDb.OleDbDataAdapter(cmd)