什么叫ListViewItem\u ItemChecked事件?

我有一个ListView,checkbox=true,View=List。在项目开始时,我会进行一些计算,确定数据库是否为空,以及从那里我应该做些什么。我要做的一件事是遍历一个包含报表名称的数组(从dll中),并将列表视图项添加到ListView中,因为我们希望它尽可能动态。如果应用程序刚刚启动,则在ListViewItem\u ItemChecked事件中( If Not _bShowAll Then )我只是让它通过,否则我称之为“昂贵”的函数。当我开始我的应用程序时,它似乎需要相当长的时间,所以我在“昂贵”函数中设置了一个断点,它被击中的次数和报告名称一样多。我知道ListViewItem.SelectedItemif set将调用ListViewItem\u ItemChecked,以及ListViewItem。选中我想还有一些。但是从初始化开始,我为ListViewItem调用的唯一函数是insert。当我在ListViedItem\u ItemChecked中放置一个断点时,我击中了断点。这是我的构造函数、ListViewItem\u ItemChecked和“昂贵”函数。

Public Sub New()
    'Initializes all of the controls on the screen and their properties.'
    InitializeComponent()
    'Sets the variable to what the Window text is at Startup'
    _strTitle = Me.Text

    'ViewModes is a dll that contains Class ViewModes and a variable ViewModes.'
    'Goes through the Dictionary(Of string, String) and adds all of the keys to the View Mode ComboBox.'
    For Each kvp As KeyValuePair(Of String, String) In ViewModes.ViewModes.ViewModes
        cmbViewMode.Items.Add(kvp.Key)
    Next

    'Sets the View Mode ComboBox to the first item that was added to it.'
    cmbViewMode.SelectedIndex = 0

    lblFigureTitle.Text = "ALL"

    _bShowAll = True

    For Each strReportName As String In _dataController.ReportNames
        lvReports.Items.Insert(lvReports.Items.Count, strReportName)
    Next

    _bShowAll = False

    'Check to see if the database has any information or not.'
    If Not _dataController.DatabaseIsEmpty Then
        'There''s no point in doing the stuff in this block if the database is Empty'

        'Sets the lable next to "IPB:" to the IPB obtained from the first record of the .out file.'
        lblIPBNumber.Text = _dataController.IPBNumber
        'Adds the IPB Number to the Window text so if it is minimized and the user has multiple'
        'instances of the app running, they can know which one is which by hovering over the bar in the Taskbar.'
        Me.Text = _strTitle + "    IPB: " + _dataController.IPBNumber
        'This builds the TreeView with the Figure names.'
        BuildFigureTree()
        'This goes through the data in the database and builds the list of reports'
        'BuildReports()'
    End If
End Sub

Private Sub lvReports_ItemChecked(ByVal sender As System.Object, ByVal e As System.Windows.Forms.ItemCheckedEventArgs) Handles lvReports.ItemChecked
    If Not e Is Nothing Then
        If cbAllReports.Checked Then
            If Not e.Item.Checked Then
                cbAllReports.Checked = False
                e.Item.Checked = True
            End If

            _lstReportFilter.Add(e.Item.Name)
        Else
            If e.Item.Checked Then
                _lstReportFilter.Add(e.Item.Name)
                cbTaggedRecords.Checked = False
            Else
                _lstReportFilter.Remove(e.Item.Name)
            End If
        End If
    Else
        For Each lvi As ListViewItem In lvReports.Items
            lvi.Checked = False
        Next
    End If

    For Each rr As ReportRecord In _lstReportRecords.Where(Function(rRecord As ReportRecord) _lstReportFilter.Contains(rRecord.Description))
        _strReportFilter += If(String.IsNullOrEmpty(_strReportFilter) Or _strReportFilter = "-1", "", ",") + rr.PartID.ToString()
    Next

    If Not _bShowAll Then
        FillDataGridView()
    End If
End Sub

Private Sub FillDataGridView()
    'Set the cursor to a wait cursor just in case it takes some time retrieving information from the db'
    Me.Cursor = Cursors.WaitCursor
    Try
        'We always want to make sure both scroll bars are visible'
        dgvParts.ScrollBars = ScrollBars.Both

        Dim strFilter As String = String.Empty

        'If there is a value in the Search TextBox, add it to the filter'
        If Not String.IsNullOrEmpty(_strSearchFilter) Then
            strFilter += If(String.IsNullOrEmpty(strFilter), " ", " and ") + _strSearchFilter
        End If

        'For us to filter on Figures, there has to be nodes in the tree.'
        If tvFigures.Nodes.Count > 0 Then
            'If the FigureTitle text equals "ALL" (set whenever a tree node is selected)'
            'then we don''t need to set a filter for figure.'
            If Not lblFigureTitle.Text = "ALL" Then
                'cbCurrentFigure is naturally not checked.  And we don''t want to filter on just that figure'
                'if the user isn''t searching for something.  So if there is a value in the search box and'
                'cbCurrentFigure is checked, then we want to look at only the selected figure.  However,'
                'if the search box is empty and cbCurrentFigure is not checked, we also want to search'
                'only on the selected figure.'
                If (Not String.IsNullOrEmpty(_strSearchFilter) And cbCurrentFigure.Checked) Or (String.IsNullOrEmpty(_strSearchFilter) And Not cbCurrentFigure.Checked) Then
                    strFilter += If(String.IsNullOrEmpty(strFilter), " ", " and ") + Constants.TransformColumnOrHeaderName("Figure") + " = '" + tvFigures.SelectedNode.Name + "'"
                End If
            Else
                strFilter += If(String.IsNullOrEmpty(strFilter), " ", " and ") + Constants.TransformColumnOrHeaderName("Figure") + " LIKE '%%' "
            End If
        End If

        'A selection of an indenture level in the combo box means we need to add a filter.  "ALL"'
        'is not a selection and needs no filter.'
        If Not cmbIndentureLevel.Text = "ALL" And Not String.IsNullOrEmpty(cmbIndentureLevel.Text) Then
            strFilter += If(String.IsNullOrEmpty(strFilter), " ", " and ") + Constants.TransformColumnOrHeaderName("Indenture") + " = " + cmbIndentureLevel.Text
        End If

        'If the user has selected any of the reports in the list view, add those to the filter.'
        If Not String.IsNullOrEmpty(_strReportFilter) Then
            strFilter += If(String.IsNullOrEmpty(strFilter), " ", " and ") + " PART_ID IN (" + _strReportFilter + ")"
        End If

        'If there is no filter, then we don''t want to view anything.'
        If Not String.IsNullOrEmpty(strFilter) Then
            'If there are validation errors from importing the file, we want to display those errors and get out.'
            If _lstValidationResults.Count > 0 Then
                dgvParts.DataSource = _lstValidationResults

                For Each col As DataGridViewColumn In dgvParts.Columns
                    col.DataPropertyName = "ErrorMessage"
                    col.Visible = True
                    col.SortMode = DataGridViewColumnSortMode.Programmatic
                    col.AutoSizeMode = DataGridViewAutoSizeColumnMode.ColumnHeader
                Next

                dgvParts.AutoResizeColumns()
                Return
            End If

            Dim bSource As BindingSource = New BindingSource()
            'We use the text from the View Mode combo box to look in a dictionary and obtain'
            'the query needed for that view.  We also send the filter so we get ONLY what we'
            'need when we''re pulling the data, instead of pulling it all and then filtering.'
            bSource.DataSource = _dataController.PopulateDataGrid(cmbViewMode.Text, strFilter).Tables(0)

            dgvParts.DataSource = bSource
            dgvParts.Columns(0).Visible = False
            'The Description Column should only be 250 characters in size.  If a description is longer'
            'than that, they need to double click the cell and a message box will pop up.'
            dgvParts.Columns("Description").Resizable = DataGridViewTriState.False
            dgvParts.Columns("Description").Width = 750

            For Each col As DataGridViewColumn In dgvParts.Columns
                'Programmatic sorting means custom sorting.  May be changed to automatic.'
                col.SortMode = DataGridViewColumnSortMode.Programmatic

                'Again, we don''t want to resize the description column, it should stay set.'
                If Not col.Name = "Description" Then
                    dgvParts.AutoResizeColumn(col.Index)
                End If

                'Because the Tags column is only reported, we do not want them to change any values'
                'in the column.'
                If col.Name.ToUpper() = "TAGS" Then
                    col.ReadOnly = True
                End If
            Next

            'Other row and cell properties.'
            dgvParts.AutoSizeRowsMode = DataGridViewAutoSizeRowsMode.DisplayedCells
            dgvParts.ShowCellToolTips = True
            dgvParts.BorderStyle = BorderStyle.Fixed3D
        End If

        FormatCells()

        'The information from here until the Catch statement goes through and counts how'
        'many records for each report there are and to set those counts into the items'
        'in the list view.'
        Dim nTotalCount As Integer = 0

        For Each lvi As ListViewItem In lvReports.Items
            Dim nCount As Integer = _lstReportRecords.Where(Function(rr As ReportRecord) lvi.Text.Contains(rr.Description)).Count()
            nTotalCount += nCount
            lvi.Text = If(lvi.Text.Contains("("), lvi.Text.Substring(0, lvi.Text.IndexOf("(") + 1), lvi.Text.Trim() + " (") + nTotalCount.ToString() + ")"
        Next

        cbAllReports.Text = If(cbAllReports.Text.Contains("("), cbAllReports.Text.Substring(0, cbAllReports.Text.IndexOf("(") + 1), cbAllReports.Text + " (") + nTotalCount.ToString() + ")"
        cbTaggedRecords.Text = If(cbTaggedRecords.Text.Contains("("), cbTaggedRecords.Text.Substring(0, cbTaggedRecords.Text.IndexOf("(") + 1), cbTaggedRecords.Text + " (") + _lstReportRecords.Where(Function(rr As ReportRecord) rr.Description.Contains("Tagged")).Count().ToString() + ")"
    Catch ex As Exception
        'An exception was thrown.  Show it to the user so they can report it.'
        MessageBox.Show(ex.Message)
    End Try
    'Change the cursor back to the default cursor'
    Me.Cursor = Cursors.Default
End Sub

在将项插入ListView之前,我确保\u bShowAll为True(意味着通过ItemChecked函数),之后为False,但我仍然使用ItemChanged函数。有人能看到我遗漏的东西吗?有没有一种方法使它更简单,或者有没有一种方法可以在不调用ItemChecked方法的情况下插入一个项?谢谢。

更新: 别担心每个人。我发现 this