gridviewhelper.vb

gridviewhelpervb cla

'------------------------------------------------------------------------------------------
' Copyright © 2006 Agrinei Sousa [www.agrinei.com]
'
' Esse código fonte é fornecido sem garantia de qualquer tipo.
' Sinta-se livre para utilizá-lo, modificá-lo e distribuí-lo,
' inclusive em aplicações comerciais.
' É altamente desejável que essa mensagem não seja removida.
'------------------------------------------------------------------------------------------

Imports System
Imports System.Collections
Imports System.Collections.Generic
Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls


Public Delegate Sub FooterEvent(ByVal row As GridViewRow)

''' <summary>
''' A class to allow you to add summaries and groups to a GridView, easily!
''' </summary>
Public Class GridViewHelper

	#Region "Fields"

	Private mGrid As GridView
	Private mGeneralSummaries As GridViewSummaryList
	Private mGroups As GridViewGroupList
	Private useFooter As Boolean
	Private groupSortDir As SortDirection

	#End Region

	Public ReadOnly Property Groups() As GridViewGroupList
		Get
			Return mGroups
		End Get
	End Property

	Public ReadOnly Property GeneralSummaries() As GridViewSummaryList
		Get
			Return mGeneralSummaries
		End Get
	End Property


	#Region "Messages"

	Private Const USE_ADEQUATE_METHOD_TO_REGISTER_THE_SUMMARY As String = "Use adequate method to register a summary with custom operation."
	Private Const GROUP_NOT_FOUND As String = "Group {0} not found. Please register the group before the summary."
	Private Const INVALID_SUMMARY As String = "Invalid summary."
	Private Const SUPPRESS_GROUP_ALREADY_DEFINED As String = "A suppress group is already defined. You can't define suppress AND summary groups simultaneously"
	Private Const ONE_GROUP_ALREADY_REGISTERED As String = "At least a group is already defined. A suppress group can't coexist with other groups"

	#End Region


	#Region "Events"

	''' <summary>
	''' Event triggered when a new group starts
	''' </summary>
	Public Event GroupStart As GroupEvent

	''' <summary>
	''' Event triggered when a group ends
	''' </summary>
	Public Event GroupEnd As GroupEvent

	''' <summary>
	''' Event triggered after a row for group header be inserted
	''' </summary>
	Public Event GroupHeader As GroupEvent

	''' <summary>
	''' Event triggered after a row for group summary be inserted
	''' </summary>
	Public Event GroupSummary As GroupEvent

	''' <summary>
	''' Event triggered after the general summaries be generated
	''' </summary>
	Public Event GeneralSummary As FooterEvent

	''' <summary>
	''' Event triggered when the footer is databound
	''' </summary>
	Public Event FooterDataBound As FooterEvent

	#End Region


	#Region "Constructors"

	Public Sub New(ByVal grd As GridView)
		Me.New(grd, False, SortDirection.Ascending)
	End Sub

	Public Sub New(ByVal grd As GridView, ByVal useFooterForGeneralSummaries As Boolean)
		Me.New(grd, useFooterForGeneralSummaries, SortDirection.Ascending)
	End Sub

	Public Sub New(ByVal grd As GridView, ByVal useFooterForGeneralSummaries As Boolean, ByVal groupSortDirection As SortDirection)
		Me.mGrid = grd
		Me.useFooter = useFooterForGeneralSummaries
		Me.groupSortDir = groupSortDirection
		Me.mGeneralSummaries = New GridViewSummaryList()
		Me.mGroups = New GridViewGroupList()
		AddHandler Me.mGrid.RowDataBound, AddressOf RowDataBoundHandler
	End Sub

	#End Region


	#Region "RegisterSummary overloads"

	Public Function RegisterSummary(ByVal column As String, ByVal operation As SummaryOperation) As GridViewSummary
		Return Me.RegisterSummary(column, [String].Empty, operation)
	End Function

	Public Function RegisterSummary(ByVal column As String, ByVal formatString As String, ByVal operation As SummaryOperation) As GridViewSummary
		If operation = SummaryOperation.[Custom] Then
			Throw New Exception(USE_ADEQUATE_METHOD_TO_REGISTER_THE_SUMMARY)
		End If

		' TO DO: Perform column validation...
		Dim s As New GridViewSummary(column, formatString, operation, Nothing)
		mGeneralSummaries.Add(s)

		' if general summaries are displayed in the footer, it must be set to visible
		If useFooter Then
			mGrid.ShowFooter = True
		End If

		Return s
	End Function

	Public Function RegisterSummary(ByVal column As String, ByVal operation As SummaryOperation, ByVal groupName As String) As GridViewSummary
		Return Me.RegisterSummary(column, [String].Empty, operation, groupName)
	End Function

	Public Function RegisterSummary(ByVal column As String, ByVal formatString As String, ByVal operation As SummaryOperation, ByVal groupName As String) As GridViewSummary
		If operation = SummaryOperation.[Custom] Then
			Throw New Exception(USE_ADEQUATE_METHOD_TO_REGISTER_THE_SUMMARY)
		End If

		Dim group As GridViewGroup = mGroups(groupName)
		If group Is Nothing Then
			Throw New Exception([String].Format(GROUP_NOT_FOUND, groupName))
		End If

		' TO DO: Perform column validation...
		Dim s As New GridViewSummary(column, formatString, operation, group)
		group.AddSummary(s)

		Return s
	End Function

	Public Function RegisterSummary(ByVal column As String, ByVal operation As CustomSummaryOperation, ByVal getResult As SummaryResultMethod) As GridViewSummary
		Return RegisterSummary(column, [String].Empty, operation, getResult)
	End Function

	Public Function RegisterSummary(ByVal column As String, ByVal formatString As String, ByVal operation As CustomSummaryOperation, ByVal getResult As SummaryResultMethod) As GridViewSummary
		' TO DO: Perform column validation...
		Dim s As New GridViewSummary(column, formatString, operation, getResult, Nothing)
		mGeneralSummaries.Add(s)

		' if general summaries are displayed in the footer, it must be set to visible
		If useFooter Then
			mGrid.ShowFooter = True
		End If

		Return s
	End Function

	Public Function RegisterSummary(ByVal column As String, ByVal operation As CustomSummaryOperation, ByVal getResult As SummaryResultMethod, ByVal groupName As String) As GridViewSummary
		Return RegisterSummary(column, [String].Empty, operation, getResult, groupName)
	End Function

	Public Function RegisterSummary(ByVal column As String, ByVal formatString As String, ByVal operation As CustomSummaryOperation, ByVal getResult As SummaryResultMethod, ByVal groupName As String) As GridViewSummary
		Dim group As GridViewGroup = mGroups(groupName)
		If group Is Nothing Then
			Throw New Exception([String].Format(GROUP_NOT_FOUND, groupName))
		End If

		' TO DO: Perform column validation...
		Dim s As New GridViewSummary(column, formatString, operation, getResult, group)
		group.AddSummary(s)

		Return s
	End Function

	Public Function RegisterSummary(ByVal s As GridViewSummary) As GridViewSummary
		If Not s.Validate() Then
			Throw New Exception(INVALID_SUMMARY)
		End If

		If s.Group Is Nothing Then
			' if general summaries are displayed in the footer, it must be set to visible
			If useFooter Then
				mGrid.ShowFooter = True
			End If

			mGeneralSummaries.Add(s)
ElseIf Not s.Group.ContainsSummary(s) Then
			s.Group.AddSummary(s)
		End If

		Return s
	End Function

	#End Region


	#Region "RegisterGroup overloads"

	Public Function RegisterGroup(ByVal column As String, ByVal auto As Boolean, ByVal hideGroupColumns As Boolean) As GridViewGroup
		Dim cols As String() = New String(0) {column}
		Return RegisterGroup(cols, auto, hideGroupColumns)
	End Function

	Public Function RegisterGroup(ByVal columns As String(), ByVal auto As Boolean, ByVal hideGroupColumns As Boolean) As GridViewGroup
		If HasSuppressGroup() Then
			Throw New Exception(SUPPRESS_GROUP_ALREADY_DEFINED)
		End If

		' TO DO: Perform column validation...
		Dim g As New GridViewGroup(columns, auto, hideGroupColumns)
		mGroups.Add(g)

		If hideGroupColumns Then
			For i As Integer = 0 To mGrid.Columns.Count - 1
				For j As Integer = 0 To columns.Length - 1
					If GetDataFieldName(mGrid.Columns(i)).ToLower() = columns(j).ToLower() Then
						mGrid.Columns(i).Visible = False
					End If
				Next
			Next
		End If

		Return g
	End Function

	#End Region


	#Region "SetSuppressGroup overloads"

	Public Function SetSuppressGroup(ByVal column As String) As GridViewGroup
		Dim cols As String() = New String(0) {column}
		Return SetSuppressGroup(cols)
	End Function

	Public Function SetSuppressGroup(ByVal columns As String()) As GridViewGroup
		If mGroups.Count > 0 Then
			Throw New Exception(ONE_GROUP_ALREADY_REGISTERED)
		End If

		' TO DO: Perform column validation...
		Dim g As New GridViewGroup(columns, True, False, False, False)
		mGroups.Add(g)

		' Disable paging because pager works in datarows that
		' will be suppressed
		mGrid.AllowPaging = False

		Return g
	End Function

	#End Region


	#Region "Private Helper functions"

	Private Function GetSequentialGroupColumns() As String
		Dim ret As String = [String].Empty

		For Each g As GridViewGroup In mGroups
			ret += g.Name.Replace("+"C, ","C) + ","
		Next
		Return ret.Substring(0, ret.Length - 1)
	End Function

	''' <summary>
	''' Compares the actual group values with the values of the current dataitem
	''' </summary>
	''' <param name="g"></param>
	''' <param name="dataitem"></param>
	''' <returns></returns>
	Private Function EvaluateEquals(ByVal g As GridViewGroup, ByVal dataitem As Object) As Boolean
		' The values wasn't initialized
		If g.ActualValues Is Nothing Then
			Return False
		End If
		For i As Integer = 0 To g.Columns.Length - 1

			If g.ActualValues(i) Is Nothing AndAlso DataBinder.Eval(dataitem, g.Columns(i)) IsNot Nothing Then
				Return False
			End If
			If g.ActualValues(i) IsNot Nothing AndAlso DataBinder.Eval(dataitem, g.Columns(i)) Is Nothing Then
				Return False
			End If
			If Not g.ActualValues(i).Equals(DataBinder.Eval(dataitem, g.Columns(i))) Then
				Return False
			End If
		Next

		Return True
	End Function

	Private Function HasSuppressGroup() As Boolean
		For Each g As GridViewGroup In mGroups
			If g.IsSuppressGroup Then
				Return True
			End If
		Next
		Return False
	End Function

	Private Function HasAutoSummary(ByVal list As List(Of GridViewSummary)) As Boolean
		For Each s As GridViewSummary In list
			If s.Automatic Then
				Return True
			End If
		Next
		Return False
	End Function

	Private Function GetGroupRowValues(ByVal g As GridViewGroup, ByVal dataitem As Object) As Object()
		Dim values As Object() = New Object(g.Columns.Length - 1) {}
		For i As Integer = 0 To g.Columns.Length - 1

			values(i) = DataBinder.Eval(dataitem, g.Columns(i))
		Next

		Return values
	End Function

	''' <summary>
	''' Inserts a grid row. Only cells required for the summary results
	''' will be created (except if GenerateAllCellsOnSummaryRow is true).
	''' The group will be checked for columns with summary
	''' </summary>
	''' <param name="beforeRow"></param>
	''' <param name="g"></param>
	''' <returns></returns>
	Private Function InsertGridRow(ByVal beforeRow As GridViewRow, ByVal g As GridViewGroup) As GridViewRow
		Dim colspan As Integer
		Dim cell As TableCell
		Dim tcArray As TableCell()
		Dim visibleColumns As Integer = Me.GetVisibleColumnCount()

		Dim tbl As Table = DirectCast(mGrid.Controls(0), Table)
		Dim newRowIndex As Integer = tbl.Rows.GetRowIndex(beforeRow)
		Dim newRow As New GridViewRow(newRowIndex, newRowIndex, DataControlRowType.DataRow, DataControlRowState.Normal)

		If g IsNot Nothing AndAlso (g.IsSuppressGroup OrElse g.GenerateAllCellsOnSummaryRow) Then
			' Create all the table cells
			tcArray = New TableCell(visibleColumns - 1) {}
			For i As Integer = 0 To visibleColumns - 1
				cell = New TableCell()
				cell.ApplyStyle(mGrid.Columns(GetRealIndexFromVisibleColumnIndex(i)).ItemStyle)
				cell.Text = "&nbsp;"
				tcArray(i) = cell
			Next
		Else
			' Create only the required table cells
			colspan = 0
			Dim tcc As New List(Of TableCell)()
			For i As Integer = 0 To mGrid.Columns.Count - 1
				If ColumnHasSummary(i, g) Then
					If colspan > 0 Then
						cell = New TableCell()
						cell.Text = "&nbsp;"
						cell.ColumnSpan = colspan
						tcc.Add(cell)
						colspan = 0
					End If

					' insert table cell and copy the style
					cell = New TableCell()
					cell.ApplyStyle(mGrid.Columns(i).ItemStyle)
					tcc.Add(cell)
ElseIf mGrid.Columns(i).Visible Then
					' A visible column that will have no cell because has
					' no summary. So we increase the colspan...
					colspan += 1
				End If
			Next

			If colspan > 0 Then
				cell = New TableCell()
				cell.Text = "&nbsp;"
				cell.ColumnSpan = colspan
				tcc.Add(cell)
				colspan = 0
			End If

			tcArray = New TableCell(tcc.Count - 1) {}
			tcc.CopyTo(tcArray)
		End If

		newRow.Cells.AddRange(tcArray)
		tbl.Controls.AddAt(newRowIndex, newRow)

		Return newRow
	End Function