如何从此代码中正确处理按钮？ [英] How do I dispose of a button properly from this code?

问题描述

我得到的错误是：



警告26 CA2000：Microsoft.Reliability：在方法'FrmManager.LoadCategories（）'中，调用System.IDisposable。在对所有引用超出范围之前对对象'btn'进行处理。



这是代码：我做错了什么？

The error I am getting is this:

Warning 26 CA2000 : Microsoft.Reliability : In method 'FrmManager.LoadCategories()', call System.IDisposable.Dispose on object 'btn' before all references to it are out of scope.

Here is the code: What am I doing wrong please?

Public Sub LoadCategories()
        Try
            If cn.State = ConnectionState.Closed Then
                cn.Open()
            End If

            Dim sql As String = "Select Category from Categories ORDER BY Category Asc"

            Using ds As New DataSet
                Using da As New OleDb.OleDbDataAdapter(sql, cn)
                da.Fill(ds)
                End Using

                If ds.Tables(0).Rows.Count = 0 Then
                    MsgBox("No categories were found.", MsgBoxStyle.Critical, "NO RECORDS!")
                    Exit Sub
                End If

                For i As Integer = 0 To ds.Tables(0).Rows.Count - 1
                    Dim btn As New Button
                    Try

                        AddHandler btn.Click, AddressOf CategoryLoadClick
                        btn.Width = 75
                        btn.Height = 50
                        btn.Text = ds.Tables(0).Rows(i)("Category").ToString
                    Catch ex As Exception
                        If Not btn Is Nothing Then
                            btn.Dispose()
                        End If
                        MsgBox(ex.Message)
                    End Try

                Next
             
                flowlayoutpanel.Controls.Add(btn)
            End Using
        Catch ex As Exception
            MsgBox(ex.Message)
        Finally
            cn.Close()
        End Try

推荐答案

将代码包含在创建按钮的位置在使用...结束使用语句中，因为如果在循环中引发任何异常，则不会处理按钮对象...

Enclose the code where you create buttons within "Using...End Using" statements because if any exception is raised in you for loop the button object will not be disposed...

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