在vb.net中找不到表 [英] Can not find table in vb.net
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问题描述
当我点击按钮然后消息框显示消息找不到table0。
这意味着什么?我怎么能解决这个问题? ??
私人 Sub butsea_Click(发件人< span class =code-keyword>作为 对象,e As EventArgs)句柄 butsea.Click
Dim dset 正如 新 DataSet
Dim da 作为 SqlDataAdapter
Dim myCmd 作为 新 SqlCommand
尝试
myConn.ConnectionString = 数据源= THEONE \ PAGEH;初始目录= testdatabase;集成安全性=真;
myConn.Open()
Dim avalue 作为 字符串 =(InputBox( 输入学生ID, < span class =code-string>搜索学生))。ToString
txt_id.Text = avalue
da = 新 SqlDataAdapter( SELECT * FROM studentdetails where student_id ='& txt_id.Text& ,myConn)
如果 dset.Tables( 0 )。Rows.Count> 0 然后
MsgBox( Record Found)
Else
MsgBox( 找不到记录)
结束 如果
Catch ex As 例外
MsgBox(ex.Message)
最后
myConn.Close()
结束 尝试
结束 Sub
解决方案
您在方法的顶部声明了一个DataSet,但是你没有实际上是c通过DataAdapter与数据库连接!尝试添加中间行:
da =新SqlDataAdapter( SELECT * FROM studentdetails,其中student_id ='& txt_id。文字& ,myConn)
da.Fill(dset)
如果 dset。表( 0 )。Rows.Count> 0 然后
Private Sub butsea_Click(发件人为对象,e为EventArgs)处理butsea.Click
Dim dset As New DataSet
Dim da As SqlDataAdapter
Dim myCmd As New SqlCommand
尝试
myConn.ConnectionString = Data Source = THEONE\PARTH; Initial Catalog = testdatabase; Integrated Security = True;
myConn.Open()
Dim avalue as String =(InputBox( 输入学生ID, 搜索学生))。ToString
txt_id.Text = avalue
da =新的SqlDataAdapter(SELECT * FROM studentdetails,其中student_id ='& txt_id.Text& ,myConn)
da.Fill(dset)
如果是dset。表( 0 )。Rows.Count > 0 然后
MsgBox( Record Found)
Else
MsgBox( 找不到记录)
结束如果
Catch ex As Exception
MsgBox(ex.Message)
最后
myConn.Close()
结束尝试
结束子
when i was click on button then message box show message "cannot find table0."
what does it means ???how can i solve this problem ????
Private Sub butsea_Click(sender As Object, e As EventArgs) Handles butsea.Click
Dim dset As New DataSet
Dim da As SqlDataAdapter
Dim myCmd As New SqlCommand
Try
myConn.ConnectionString = "Data Source=THEONE\PARTH;Initial Catalog=testdatabase;Integrated Security=True;"
myConn.Open()
Dim avalue As String = (InputBox("Input Student Id", "Search Student")).ToString
txt_id.Text = avalue
da = New SqlDataAdapter("SELECT * FROM studentdetails where student_id= '" & txt_id.Text & "", myConn)
If dset.Tables(0).Rows.Count > 0 Then
MsgBox("Record Found")
Else
MsgBox("No Record Found")
End If
Catch ex As Exception
MsgBox(ex.Message)
Finally
myConn.Close()
End Try
End Sub
解决方案
You declare a DataSet at the top of your method, but you don't actually connect it with the database via the DataAdapter! Try adding the middle line:
da = New SqlDataAdapter("SELECT * FROM studentdetails where student_id= '" & txt_id.Text & "", myConn) da.Fill(dset) If dset.Tables(0).Rows.Count > 0 Then
Private Sub butsea_Click(sender As Object, e As EventArgs) Handles butsea.Click Dim dset As New DataSet Dim da As SqlDataAdapter Dim myCmd As New SqlCommand Try myConn.ConnectionString = "Data Source=THEONE\PARTH;Initial Catalog=testdatabase;Integrated Security=True;" myConn.Open() Dim avalue As String = (InputBox("Input Student Id", "Search Student")).ToString txt_id.Text = avalue da = New SqlDataAdapter("SELECT * FROM studentdetails where student_id= '" & txt_id.Text & "", myConn) da.Fill(dset) If dset.Tables(0).Rows.Count > 0 Then MsgBox("Record Found") Else MsgBox("No Record Found") End If Catch ex As Exception MsgBox(ex.Message) Finally myConn.Close() End Try End Sub
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