I am trying really hard to grasp the concept of Interfaces and their real
world usage.
I constructed a simple project of a webpage that contains two controls. I
am enabling communication back and forth between the page as well as
controls. I used two interfaces to remove the hardcoded references.
Is what I'm doing correct? Any suggestions?
Thanks!
Ron
SamplePage.aspx.vb------------------------------------------------------------------
Public Class SamplePage
Inherits System.Web.UI.Page
Implements IResultContainer
Private RR As Results
Private RH As ResultHeader
Private _Title As String
Public ReadOnly Property Title() As String Implements IResultContainer.Title
Get
Return Page.ToString
End Get
End Property
Public ReadOnly Property Results() As IResult Implements
IResultContainer.IResults
Get
Return RR
End Get
End Property
Public ReadOnly Property Header() As ResultHeader Implements
IResultContainer.ResultHeader
Get
Return RH
End Get
End Property
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
RR = CType(Page.LoadControl("Results.ascx"), Results)
RH = CType(Page.LoadControl("ResultHeader.ascx"), ResultHeader)
End Sub
End Class
SamplePage.Aspx -----------------------------------------------------------------------
<%@ Page Language="vb" AutoEventWireup="false"
Codebehind="SamplePage.aspx.vb" Inherits="Communications.SamplePage"%>
<%@ Register TagPrefix="Result" TagName="Results" Src="Results.ascx" %>
<%@ Register TagPrefix="Result" TagName="Header" Src="ResultHeader.ascx" %>
<HTML>
<body>
<form id="Form1" method="post" runat="server">
<Result:Results id="rr" runat="server" />
<Result:Header id="rh" runat="server" />
</form>
</body>
</HTML>
Results.ascx--------------------------------------------------------------------------------------
Public Class Results
Inherits System.Web.UI.UserControl
Implements IResult
#Region " Web Form Designer Generated Code "
'This call is required by the Web Form Designer.
<System.Diagnostics.DebuggerStepThrough()Private Sub InitializeComponent()
End Sub
'NOTE: The following placeholder declaration is required by the Web Form
Designer.
'Do not delete or move it.
Private designerPlaceholderDeclaration As System.Object
Private Sub Page_Init(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Init
'CODEGEN: This method call is required by the Web Form Designer
'Do not modify it using the code editor.
InitializeComponent()
End Sub
#End Region
Private _Info As DataTable
Private _Title As String
Private _RowCount As String
Public Property RowCount() As String Implements IResult.RowCount
Get
_RowCount = GetRowCount()
Return _RowCount
End Get
Set(ByVal Value As String)
_RowCount = Value
End Set
End Property
Public Property Info() As DataTable Implements IResult.Info
Get
_Info = GetAllResults()
Return _Info
End Get
Set(ByVal Value As DataTable)
_Info = Value
End Set
End Property
Private Function GetAllResults() As DataTable
Dim dt As New DataTable
Dim dc As DataColumn
Dim dr As DataRow
dc = New DataColumn("Col1")
dc.DataType = System.Type.GetType("System.String")
dt.Columns.Add(dc)
dr = dt.NewRow
dr.Item("Col1") = "Row1 Col1"
dt.Rows.Add(dr)
dr = dt.NewRow
dr.Item("Col1") = "Row2 Col1"
dt.Rows.Add(dr)
Return dt
End Function
Private Function GetRowCount() As String
Return _Info.Rows.Count
End Function
End Class
Results.ascx-----------------------------------------------------------
Public Class ResultHeader
Inherits System.Web.UI.UserControl
Protected WithEvents DataGrid1 As System.Web.UI.WebControls.DataGrid
Protected WithEvents TextBox1 As System.Web.UI.WebControls.TextBox
Protected _Info As DataTable
Protected _Title As String
Protected _RowCount As String
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
If TypeOf (Page) Is IResultContainer Then
_Info = CType(Page, IResultContainer).IResults.Info
_Title = CType(Page, IResultContainer).Title
_RowCount = CType(Page, IResultContainer).IResults.RowCount
BindGrid()
TextBox1.Text = _Title & " Returned " & _RowCount & " rows"
End If
End Sub
Private Sub BindGrid()
DataGrid1.DataSource = (_Info)
DataGrid1.DataBind()
End Sub
End Class
Interfaces-----------------------------------------------------------------------------------
Public Interface IResultContainer
ReadOnly Property ResultHeader() As ResultHeader
ReadOnly Property Title() As String
ReadOnly Property IResults() As IResult
End Interface
Public Interface IResult
Property Info() As DataTable
Property RowCount() As String
End Interface
2  1269 
Looks good to me.
Looking @ the code, I assume your user control can't work if the page
doesn't implement IResultContainer. If so, I'd go the extra step and throw
an exception in that case.
I would also avoid the multiple ctypes and do it once...
if typeof(Page)... then
dim container as IResultContainer = ctype(Page, IResultContainer)
container...
container..
end if
-- http://www.openmymind.net/ http://www.fuelindustries.com/
"RSH" <wa*************@yahoo.comwrote in message
news:%2***************@TK2MSFTNGP06.phx.gbl...
>I am trying really hard to grasp the concept of Interfaces and their real
world usage.
I constructed a simple project of a webpage that contains two controls. I
am enabling communication back and forth between the page as well as
controls. I used two interfaces to remove the hardcoded references.
Is what I'm doing correct? Any suggestions?
Thanks!
Ron
SamplePage.aspx.vb------------------------------------------------------------------
Public Class SamplePage
Inherits System.Web.UI.Page
Implements IResultContainer
Private RR As Results
Private RH As ResultHeader
Private _Title As String
Public ReadOnly Property Title() As String Implements
IResultContainer.Title
Get
Return Page.ToString
End Get
End Property
Public ReadOnly Property Results() As IResult Implements
IResultContainer.IResults
Get
Return RR
End Get
End Property
Public ReadOnly Property Header() As ResultHeader Implements
IResultContainer.ResultHeader
Get
Return RH
End Get
End Property
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
RR = CType(Page.LoadControl("Results.ascx"), Results)
RH = CType(Page.LoadControl("ResultHeader.ascx"), ResultHeader)
End Sub
End Class
SamplePage.Aspx -----------------------------------------------------------------------
<%@ Page Language="vb" AutoEventWireup="false"
Codebehind="SamplePage.aspx.vb" Inherits="Communications.SamplePage"%>
<%@ Register TagPrefix="Result" TagName="Results" Src="Results.ascx" %>
<%@ Register TagPrefix="Result" TagName="Header" Src="ResultHeader.ascx"
%>
<HTML>
<body>
<form id="Form1" method="post" runat="server">
<Result:Results id="rr" runat="server" />
<Result:Header id="rh" runat="server" />
</form>
</body>
</HTML>
Results.ascx--------------------------------------------------------------------------------------
Public Class Results
Inherits System.Web.UI.UserControl
Implements IResult
#Region " Web Form Designer Generated Code "
'This call is required by the Web Form Designer.
<System.Diagnostics.DebuggerStepThrough()Private Sub
InitializeComponent()
End Sub
'NOTE: The following placeholder declaration is required by the Web Form
Designer.
'Do not delete or move it.
Private designerPlaceholderDeclaration As System.Object
Private Sub Page_Init(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Init
'CODEGEN: This method call is required by the Web Form Designer
'Do not modify it using the code editor.
InitializeComponent()
End Sub
#End Region
Private _Info As DataTable
Private _Title As String
Private _RowCount As String
Public Property RowCount() As String Implements IResult.RowCount
Get
_RowCount = GetRowCount()
Return _RowCount
End Get
Set(ByVal Value As String)
_RowCount = Value
End Set
End Property
Public Property Info() As DataTable Implements IResult.Info
Get
_Info = GetAllResults()
Return _Info
End Get
Set(ByVal Value As DataTable)
_Info = Value
End Set
End Property
Private Function GetAllResults() As DataTable
Dim dt As New DataTable
Dim dc As DataColumn
Dim dr As DataRow
dc = New DataColumn("Col1")
dc.DataType = System.Type.GetType("System.String")
dt.Columns.Add(dc)
dr = dt.NewRow
dr.Item("Col1") = "Row1 Col1"
dt.Rows.Add(dr)
dr = dt.NewRow
dr.Item("Col1") = "Row2 Col1"
dt.Rows.Add(dr)
Return dt
End Function
Private Function GetRowCount() As String
Return _Info.Rows.Count
End Function
End Class
Results.ascx-----------------------------------------------------------
Public Class ResultHeader
Inherits System.Web.UI.UserControl
Protected WithEvents DataGrid1 As System.Web.UI.WebControls.DataGrid
Protected WithEvents TextBox1 As System.Web.UI.WebControls.TextBox
Protected _Info As DataTable
Protected _Title As String
Protected _RowCount As String
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
If TypeOf (Page) Is IResultContainer Then
_Info = CType(Page, IResultContainer).IResults.Info
_Title = CType(Page, IResultContainer).Title
_RowCount = CType(Page, IResultContainer).IResults.RowCount
BindGrid()
TextBox1.Text = _Title & " Returned " & _RowCount & " rows"
End If
End Sub
Private Sub BindGrid()
DataGrid1.DataSource = (_Info)
DataGrid1.DataBind()
End Sub
End Class
Interfaces-----------------------------------------------------------------------------------
Public Interface IResultContainer
ReadOnly Property ResultHeader() As ResultHeader
ReadOnly Property Title() As String
ReadOnly Property IResults() As IResult
End Interface
Public Interface IResult
Property Info() As DataTable
Property RowCount() As String
End Interface
Thanks Karl!
BTW you might recognize the exersize :-)
I was trying to really "get it" I was concerned about how to make sure that
the Container page contains both of the controls. i understand the
implementation of the IResultHeader interface but I was unsure how to
implement the iResults interface in this context. I found that this worked
but if it is a proper implementation I need to dive in and really try to
grasp it.
thanks!
Ron
"Karl Seguin" <ka********@removeopenmymindremovemetoo.andmenetwr ote in
message news:uT**************@TK2MSFTNGP02.phx.gbl...
Looks good to me.
Looking @ the code, I assume your user control can't work if the page
doesn't implement IResultContainer. If so, I'd go the extra step and throw
an exception in that case.
I would also avoid the multiple ctypes and do it once...
if typeof(Page)... then
dim container as IResultContainer = ctype(Page, IResultContainer)
container...
container..
end if
--
http://www.openmymind.net/
http://www.fuelindustries.com/
"RSH" <wa*************@yahoo.comwrote in message
news:%2***************@TK2MSFTNGP06.phx.gbl...
>>I am trying really hard to grasp the concept of Interfaces and their real
world usage.
I constructed a simple project of a webpage that contains two controls.
I am enabling communication back and forth between the page as well as
controls. I used two interfaces to remove the hardcoded references.
Is what I'm doing correct? Any suggestions?
Thanks!
Ron
SamplePage.aspx.vb------------------------------------------------------------------
Public Class SamplePage
Inherits System.Web.UI.Page
Implements IResultContainer
Private RR As Results
Private RH As ResultHeader
Private _Title As String
Public ReadOnly Property Title() As String Implements
IResultContainer.Title
Get
Return Page.ToString
End Get
End Property
Public ReadOnly Property Results() As IResult Implements
IResultContainer.IResults
Get
Return RR
End Get
End Property
Public ReadOnly Property Header() As ResultHeader Implements
IResultContainer.ResultHeader
Get
Return RH
End Get
End Property
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
RR = CType(Page.LoadControl("Results.ascx"), Results)
RH = CType(Page.LoadControl("ResultHeader.ascx"), ResultHeader)
End Sub
End Class
SamplePage.Aspx -----------------------------------------------------------------------
<%@ Page Language="vb" AutoEventWireup="false"
Codebehind="SamplePage.aspx.vb" Inherits="Communications.SamplePage"%>
<%@ Register TagPrefix="Result" TagName="Results" Src="Results.ascx" %>
<%@ Register TagPrefix="Result" TagName="Header" Src="ResultHeader.ascx"
%>
<HTML>
<body>
<form id="Form1" method="post" runat="server">
<Result:Results id="rr" runat="server" />
<Result:Header id="rh" runat="server" />
</form>
</body>
</HTML>
Results.ascx--------------------------------------------------------------------------------------
Public Class Results
Inherits System.Web.UI.UserControl
Implements IResult
#Region " Web Form Designer Generated Code "
'This call is required by the Web Form Designer.
<System.Diagnostics.DebuggerStepThrough()Privat e Sub
InitializeComponent()
End Sub
'NOTE: The following placeholder declaration is required by the Web Form
Designer.
'Do not delete or move it.
Private designerPlaceholderDeclaration As System.Object
Private Sub Page_Init(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Init
'CODEGEN: This method call is required by the Web Form Designer
'Do not modify it using the code editor.
InitializeComponent()
End Sub
#End Region
Private _Info As DataTable
Private _Title As String
Private _RowCount As String
Public Property RowCount() As String Implements IResult.RowCount
Get
_RowCount = GetRowCount()
Return _RowCount
End Get
Set(ByVal Value As String)
_RowCount = Value
End Set
End Property
Public Property Info() As DataTable Implements IResult.Info
Get
_Info = GetAllResults()
Return _Info
End Get
Set(ByVal Value As DataTable)
_Info = Value
End Set
End Property
Private Function GetAllResults() As DataTable
Dim dt As New DataTable
Dim dc As DataColumn
Dim dr As DataRow
dc = New DataColumn("Col1")
dc.DataType = System.Type.GetType("System.String")
dt.Columns.Add(dc)
dr = dt.NewRow
dr.Item("Col1") = "Row1 Col1"
dt.Rows.Add(dr)
dr = dt.NewRow
dr.Item("Col1") = "Row2 Col1"
dt.Rows.Add(dr)
Return dt
End Function
Private Function GetRowCount() As String
Return _Info.Rows.Count
End Function
End Class
Results.ascx-----------------------------------------------------------
Public Class ResultHeader
Inherits System.Web.UI.UserControl
Protected WithEvents DataGrid1 As System.Web.UI.WebControls.DataGrid
Protected WithEvents TextBox1 As System.Web.UI.WebControls.TextBox
Protected _Info As DataTable
Protected _Title As String
Protected _RowCount As String
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
If TypeOf (Page) Is IResultContainer Then
_Info = CType(Page, IResultContainer).IResults.Info
_Title = CType(Page, IResultContainer).Title
_RowCount = CType(Page, IResultContainer).IResults.RowCount
BindGrid()
TextBox1.Text = _Title & " Returned " & _RowCount & " rows"
End If
End Sub
Private Sub BindGrid()
DataGrid1.DataSource = (_Info)
DataGrid1.DataBind()
End Sub
End Class
Interfaces-----------------------------------------------------------------------------------
Public Interface IResultContainer
ReadOnly Property ResultHeader() As ResultHeader
ReadOnly Property Title() As String
ReadOnly Property IResults() As IResult
End Interface
Public Interface IResult
Property Info() As DataTable
Property RowCount() As String
End Interface
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