ASP.net 2.0 自定义控件的开发之数据分页第二章

以下为控件的主要部分 (UI 部分)

通知使用基于合成的实现的服务器控件创建它们包含的任何子控件，以便为回发或呈现做准备。

Protected Overrides Sub CreateChildControls()Sub CreateChildControls()

Controls.Clear()

labPageInfo = New Label()

labPageInfoText_01 = New Label

labPageInfoText_01.Text = "每页"

txtPageSize = New TextBox

txtPageSize.ID = "txtPageSize"

txtPageSize.Width = 66

labPageInfoText_02 = New Label

labPageInfoText_02.Text = "条记录"

labPageInfoText_03 = New Label

labPageInfoText_03.Text = "转到"

labPageInfoText_04 = New Label

labPageInfoText_04.Text = "页"

txtPageIndex = New TextBox

txtPageIndex.ID = "txtPageIndex"

txtPageIndex.Width = 66

ibGotoPage = New ImageButton

ibGotoPage.ID = "ibGotoPage"

ibGotoPage.Width = 60

ibGotoPage.Height = 20

AddHandler ibGotoPage.Click, AddressOf ibGotoPage_Click

lbGotoPage = New LinkButton

lbGotoPage.ID = "lbGotoPage"

lbGotoPage.Text = "转到"

AddHandler lbGotoPage.Click, AddressOf lbGotoPage_Click

lbFirstPage = New LinkButton

lbFirstPage.ID = "lbFirstPage"

lbFirstPage.Text = "首页"

AddHandler lbFirstPage.Click, AddressOf lbFirstPage_Click

lbPrevPage = New LinkButton

lbPrevPage.ID = "lbPrevPage"

lbPrevPage.Text = "上页"

AddHandler lbPrevPage.Click, AddressOf lbPrevPage_Click

lbNextPage = New LinkButton

lbNextPage.ID = "lbNextPage"

lbNextPage.Text = "下页"

AddHandler lbNextPage.Click, AddressOf lbNextPage_Click

lbLastPage = New LinkButton

lbLastPage.ID = "lbLastPage"

lbLastPage.Text = "末页"

AddHandler lbLastPage.Click, AddressOf lbLastPage_Click

Me.Controls.Add(labPageInfo)

Me.Controls.Add(labPageInfoText_01)

Me.Controls.Add(txtPageSize)

Me.Controls.Add(labPageInfoText_02)

Me.Controls.Add(labPageInfoText_03)

Me.Controls.Add(txtPageIndex)

Me.Controls.Add(ibGotoPage)

Me.Controls.Add(lbGotoPage)

Me.Controls.Add(lbFirstPage)

Me.Controls.Add(lbPrevPage)

Me.Controls.Add(lbNextPage)

Me.Controls.Add(lbLastPage)

End Sub

重写控件的输出。

Protected Overrides Sub Render()Sub Render(ByVal writer As HtmlTextWriter)

AddAttributesToRender(writer)

writer.AddAttribute(HtmlTextWriterAttribute.Cellpadding, "1", False)

writer.AddAttribute(HtmlTextWriterAttribute.Width, "100%", False)

writer.RenderBeginTag(HtmlTextWriterTag.Table)

writer.RenderBeginTag(HtmlTextWriterTag.Tr)

writer.RenderBeginTag(HtmlTextWriterTag.Td)

writer.AddStyleAttribute(HtmlTextWriterStyle.Width, "50%")

labPageInfo.Text = "共 " & RecordCount & "条记录共 " & PageCount & " 页当前第" & CurrentPageIndex & "页"

labPageInfo.RenderControl(writer)

writer.RenderEndTag()

writer.RenderBeginTag(HtmlTextWriterTag.Td)

writer.AddStyleAttribute(HtmlTextWriterStyle.Width, "50%")

labPageInfoText_01.RenderControl(writer)

writer.WriteLine(" ")

txtPageSize.RenderControl(writer)

writer.WriteLine(" ")

labPageInfoText_02.RenderControl(writer)

writer.WriteLine(" ")

If GoToStyle = StyleGoTo.ImageButton Then

labPageInfoText_03.RenderControl(writer)

Else

lbGotoPage.RenderControl(writer)

End If

writer.WriteLine(" ")

txtPageIndex.RenderControl(writer)

writer.WriteLine(" ")

labPageInfoText_04.RenderControl(writer)

If GoToStyle = StyleGoTo.ImageButton Then

ibGotoPage.Attributes.Add("onmouseover", "this.src='" + HoverImageUrl + "';")

ibGotoPage.Attributes.Add("onmouseout", "this.src='" + DefaultImageUrl + "';")

ibGotoPage.Attributes.Add("onmouseDown", "this.src='" + PressedImageUrl + "';")

ibGotoPage.RenderControl(writer)

End If

writer.WriteLine(" ")

lbFirstPage.RenderControl(writer)

writer.WriteLine(" ")

lbPrevPage.RenderControl(writer)

writer.WriteLine(" ")

lbNextPage.RenderControl(writer)

writer.WriteLine(" ")

lbLastPage.RenderControl(writer)

writer.RenderEndTag()

End Sub

由复合控件的标准设计器用于在设计时重建控件树。

MSDN 中的解释重新创建派生自 CompositeControl 的控件的子控件。

Protected Overrides Sub RecreateChildControls()Sub RecreateChildControls()

EnsureChildControls()

End Sub

数据库分页部分，后面将给出分页的SQL Server 存储过程。

Protected Function GoToPage()Function GoToPage() As DataTable

Dim dt As New DataTable()

Conn = New SqlConnection(SQLConnection)

Conn.Open()

Using Conn

Dim Command As New SqlCommand

Command.Connection = Conn

Command.CommandText = StoredProcedureName

Command.CommandType = CommandType.StoredProcedure

Dim Parameter As SqlParameter

Parameter = Command.Parameters.Add("@Table", SqlDbType.NVarChar)

Parameter.Value = TableName

Parameter = Command.Parameters.Add("@PrimaryKeyField", SqlDbType.NVarChar)

Parameter.Value = PrimaryKeyField

Parameter = Command.Parameters.Add("@Field", SqlDbType.NVarChar)

Parameter.Value = Field

Parameter = Command.Parameters.Add("@Where", SqlDbType.NVarChar)

Parameter.Value = Where

Parameter = Command.Parameters.Add("@GroupBy", SqlDbType.NVarChar)

Parameter.Value = GroupBy

Parameter = Command.Parameters.Add("@OrderBy", SqlDbType.NVarChar)

Parameter.Value = OrderBy

Parameter = Command.Parameters.Add("@PageNumber", SqlDbType.NVarChar)

Parameter.Value = CurrentPageIndex

Parameter = Command.Parameters.Add("@PageSize", SqlDbType.NVarChar)

Parameter.Value = PageSize

Parameter = Command.Parameters.Add("@RecordCount", SqlDbType.Int)

Parameter.Direction = ParameterDirection.Output

Command.ExecuteNonQuery()

intRecordCount = Command.Parameters("@RecordCount").Value

ViewState("RecordCount") = intRecordCount

ViewState("PageCount") = Fix(intRecordCount / PageSize) + 1

Dim da As New SqlDataAdapter(Command)

da.Fill(dt)

Return dt

End Using

End Function

数据绑定代码

Public Overrides Sub DataBind()Sub DataBind()

'查找页面中的GridView及DataList并绑定数据

Dim objGridView As New GridView

Dim objDataList As New DataList

If ControlToPaginate = "" Then

Exit Sub

End If

_controlToPaginat = Page.FindControl(ControlToPaginate)

If (_controlToPaginat Is Nothing) Then

Exit Sub

End If

If (TypeOf _controlToPaginat Is GridView) Then

objGridView = CType(_controlToPaginat, GridView)

objGridView.DataSource = GoToPage()

objGridView.DataBind()

End If

If (TypeOf _controlToPaginat Is DataList) Then

objDataList = CType(_controlToPaginat, DataList)

objDataList.DataSource = GoToPage.DefaultView

objDataList.DataBind()

End If

End Sub

ASP.net 2.0 自定义控件的开发之数据分页 第二章

ASP.net 2.0 自定义控件的开发之数据分页第二章