從字符串「」轉換爲「長」類型的轉換無效。 VB.net

Question

我試圖查看從datagridview到文本框和圖片框的圖像的所有信息。但是如果我的Isbn有破折號（ - ）或字母，那就錯了。

我的代碼是這些

Private Sub Load_Image(ByVal iIMageID As Long) 
    Dim sConnString As String 

    Dim arrImage() As Byte 
    Dim myMS As New IO.MemoryStream 

    Dim reader As MySqlDataReader 


    Try 

     Call ConnectDatabase() 


     Dim query As String 
     query = "select ISBN, Subject, BookName, Publisher, Author, PublishingYear, Status, image from Books where ISBN= " & iIMageID 
     Command = New MySqlCommand(query, conn) 
     reader = Command.ExecuteReader 

     If reader.HasRows Then 
      While reader.Read 

       Label2.Text = reader("ISBN") 
       Label3.Text = reader("Subject") 
       Label1.Text = reader("BookName") 
       Label4.Text = reader("Publisher") 
       Label5.Text = reader("Author") 
       Label6.Text = reader("PublishingYear") 
       Label7.Text = reader("Status") 



       arrImage = reader("image") 
       For Each ar As Byte In arrImage 
        myMS.WriteByte(ar) 
       Next 
       ' 
       Me.PictureBox1.Image = System.Drawing.Image.FromStream(myMS) 
      End While 
     End If 

    Catch ex As Exception 
     MsgBox(ErrorToString) 
    Finally 
     conn.Close() 
    End Try 
End Sub 

然後在CellcontentClick事件

Load_Image(Me.MetroGrid1.Item(0, Me.MetroGrid1.CurrentRow.Index).Value.ToString) 

Answer 1

該參數的LoadImage被定義爲長。嘗試使用字符串代替。

Private Sub Load_Image(ByVal iIMageID As String) 

您還必須將單引號添加到SQL調用中。

query = "select ISBN, Subject, BookName, Publisher, Author, PublishingYear, Status, image from Books where ISBN= '" & iIMageID & "'" 

爲了安全起見，考慮創建一個存儲過程並調用它。