我在使用Visual Studio在我的其他窗口中形成相同的代码它正常工作但我现在在另一种形式上使用它并且它不再过滤我不知道为什么。
我试图在datagrid视图中显示一个列表,并使用两个组合框过滤它。以下是该主题的示例数据库:
-------------------------------------------------------------------------------
|subject_id|subject_name|subject_code|subject_units| sem |year_level
------------------------------------------------------------------------------
| 1 | MATH | Math101 | 3 |First Semester | First Year
| 2 | English | ENG101 | 3 |First Semester | First Year
| 3 | Prgrming | IT101 | 3 |Second Semester| First Year
| 4 | Networking| IT203 | 3 |Second Semester| First Year
这是我的代码。
myconn = New MySqlConnection
myconn.ConnectionString = connstring
myconn.Open()
tables = ds.Tables
ds = New DataSet
tables = ds.Tables
Dim Query As String
Query = "selct * from subject_bsit"
'*** CHECKING IF ALL REQUIRED FIELDS ARE PRESENT *****
If ComboBox1.Text = "" Or ComboBox2.Text = "" Then
MessageBox.Show("Complete all fields.")
Exit Sub
End If
If (ComboBox1.Text = "All") And (ComboBox2.Text = "First Semester") Then
da = New MySqlDataAdapter("Select subject_id as 'ID',subject_name as 'SUBJECT',subject_code as 'SUBJECT CODE',subject_units as 'UNITS',sem as 'Semester',year_level as 'YEAR LEVEL' from subject_bsit where sem = '" + ComboBox2.Text + "' or year_level = '" + ComboBox1.Text + "' ", myconn)
da.Fill(ds, "subject_bsit")
Dim view As New DataView(tables(0))
source1.DataSource = view
DataGridView1.DataSource = view
DataGridView1.AutoResizeColumns(DataGridViewAutoSizeColumnsMode.AllCells)
End If
正如你在样本图片中看到的那样,结果必须是全年水平第一年到第四年,但只有所有第一学期的科目,但在图片中它也显示第二学期。
它让我感到困惑,因为我有其他形式的完全相同的代码,但它正常工作。请非常感谢你。
您只需要像这样在sql字符串中用“和”替换逻辑运算符“或”:
来自subject_bsit,其中sem ='“+ ComboBox2.Text +”'和year_level ='“+ ComboBox1.Text +”'“,myconn)
我希望这可以帮助你兄弟,^ _ ^
重新启动Visual Studio可以解决问题。