抱歉我的英文
我想问一下如何检查行中是否有值?
提前感谢:)
Private Sub uploadpic()
Dim SQLCmd As New MySqlCommand("SELECT Picture FROM Student_information WHERE S_I_D = ('" & ListView1.Items(ListView1.FocusedItem.Index).SubItems(0).Text & "') ", dbcon)
dbcon.Open()
*Dim pictureData As Byte() = DirectCast(SQLCmd.ExecuteScalar(), Byte())*
dbcon.Close()
Dim picture As Image = Nothing
'Create a stream in memory containing the bytes that comprise the image.
Using stream As New IO.MemoryStream(pictureData)
'Read the stream and create an Image object from the data.
PictureBox4.Image = Image.FromStream(stream)
End Using
End Sub
答案 0 :(得分:1)
SQLCmd.ExecuteScalar()
将返回空引用。因此,您可以检查该值以了解行中是否有值。
答案 1 :(得分:0)
试试这个
Dim sql As string("SELECT Picture FROM Student_information WHERE S_I_D = ('{0}')",ListView1.Items(ListView1.FocusedItem.Index).SubItems(0).Text)
tbl = GetRecords(sql)
If tbl.Rows.Count > 0 Then
'Code to execute
Else
exit sub 'or msgbox "record not found"
End If
Public Function GetRecords(ByVal sql As String) As DataTable
Return GetRecordsExtracted(sql)
End Function
Private Function GetRecordsExtracted(ByVal sql As String) As DataTable
Dim da As New SqlClient.SqlDataAdapter
tbl = New DataTable
da = New SqlClient.SqlDataAdapter(sql, dbcon.Open)
da.Fill(tbl)
Return tbl
End Function