.net 2010 VB.NET Xml Winforms - 保留 MDI 子位置和状态

Question

我知道已经有人问过类似的问题，但这是我的问题。

在 MDI WinForm 中，我想保存每个应用程序用户的每个子窗口位置和状态，这与登录的 Windows 用户不同。我的应用程序有自己的用户；所以我不会使用像 my.Settings... 等用户设置。

一种选择是直接读/写数据库，但我不喜欢访问数据库来处理像 Windows 位置这样琐碎的事情。优点是我可以通过用户工作的机器独立存储这些信息，无论她在哪里登录，她的偏好都会被记住。

我想要遵循的另一个选择是使用 Xml 将该信息存储在用户计算机本地的文件中。结构可能是这样的：

<form name="form name">
    <Top>120</Top>
            <Left>100</Left>
            <State>0</State>
    </form>

    <form name="another form">
        <Top>120</Top>
            <Left>120</Left>
            <State>1</State>
    </form>

我很难理解这是如何做到的；也许使用 Linq to Xml？我发现我可以写一些简单的东西，例如

Dim formPos As XElement = _
    <User><%= My.Application.connectedUser.id %>
                <form1>
                    <Top>120</Top>
                    <Left>100</Left>
                    <State>0</State>
                </form1>

                <form2>
                    <Top>120</Top>
                    <Left>100</Left>
                    <State>0</State>
                </form2>
         </User>

但是：

1）如何动态填充xml选项：我想要

<User id="1"> 

而不是 <%= My.Application.connectedUser.id %> 转换为 1

2) 完成构建后如何编写 XElement它。我应该使用 XmlWriter.Create 吗？热衷于将 XElement 传递给它吗？

3）当Xml文件中已经有一个同名的节点时会发生什么，我想覆盖以前的用户设置（如果它们已经存在），但不追加到文件，也不重写整个文件，当然

谢谢。

Answer 1

它可能对其他人有用：

Public Shared Sub SaveWindowPosition(ByVal formToSave As Form, ByVal userid As Integer)

        Dim formPosLeft As Integer = formToSave.Location.X
        Dim formPosTop As Integer = formToSave.Location.Y
        Dim formDimWidth As Integer = formToSave.Width
        Dim formDimHeight As Integer = formToSave.Height
        Dim formState As Integer = formToSave.WindowState
        Dim formName As String = formToSave.Name


        '   Apri il file dove memorizzo le posizioni delle varie form
        '
        Dim xdoc As XDocument
        Try
            xdoc = XDocument.Load(FILE_NAME)
        Catch ex As Exception
            '   Non trovato, va creato uno nuovo
            '
            Dim settings As New XmlWriterSettings()
            settings.Indent = True
            Dim writer As XmlWriter = XmlWriter.Create(FILE_NAME, settings)

            writer.WriteStartDocument()
            writer.WriteStartElement("Root")

            writer.WriteEndElement()
            writer.WriteEndDocument()
            writer.Close()

            Try
                xdoc = XDocument.Load(FILE_NAME)
            Catch ex2 As Exception
                '   Nemmeno questa volta è riuscito ad aprire il file, basta
                '
                Exit Sub
            End Try
        End Try

        Dim elementRoot As XElement = xdoc.Element("Root")

        '   Cerca l'utente corrente (per id)
        '
        Dim cercaUtente As IEnumerable(Of XElement) =
            From c In elementRoot.Elements("Utente") Where c.Attribute("id").Value = CStr(userid)
        Select c
        If cercaUtente.Count = 0 Then
            '   Utente non trovato, crealo con tutti gli altri elementi
            '
            Dim xutente As XElement =
                <Utente id=<%= userid %>>
                    <Form name=<%= formName %>>
                        <Position top=<%= formPosTop %> left=<%= formPosLeft %> width=<%= formDimWidth %> height=<%= formDimHeight %> state=<%= formState %>></Position>
                    </Form>
                </Utente>

            elementRoot.Add(xutente)
        Else

            '   Utente trovato, cerca la form 
            '
            Dim cercaForm As IEnumerable(Of XElement) =
                From c In cercaUtente.Elements("Form") Where c.Attribute("name").Value = formName
            Select c

            If cercaForm.Count = 0 Then
                '   Form non trovata, creala
                '
                Dim formPos As XElement = _
                    <Form name=<%= formName %>>
                        <Position top=<%= formPosTop %> left=<%= formPosLeft %> width=<%= formDimWidth %> height=<%= formDimHeight %> state=<%= formState %>></Position>
                    </Form>

                cercaUtente.ElementAt(0).Add(formPos)
            Else
                '   Trovato tutto, sostituisci gli attributi
                '
                Dim position As XElement = cercaForm.ElementAt(0).Element("Position")
                position.ReplaceAttributes(
                    {
                        New XAttribute("top", formPosTop),
                        New XAttribute("left", formPosLeft),
                        New XAttribute("width", formDimWidth),
                        New XAttribute("height", formDimHeight),
                        New XAttribute("state", formState)
                    })

            End If
        End If

        '   Salva il file
        '
        xdoc.Save(FILE_NAME)
    End Sub






Public Shared Sub SetWindowPosition(ByVal formToPosition As Form, ByVal userid As Integer)

        formToPosition.SuspendLayout()

        Dim xdoc As XDocument
        Try
            xdoc = XDocument.Load(FILE_NAME)
        Catch ex As Exception
            '   File non trovato, nulla da fare
            '
            Exit Sub
        End Try

        Dim elementRoot As XElement = xdoc.Element("Root")

        '   Cerca l'utente corrente (per id)
        '
        Dim cercaUtente As IEnumerable(Of XElement) =
            From c In elementRoot.Elements("Utente") Where c.Attribute("id").Value = CStr(userid)
        Select c
        If cercaUtente.Count = 0 Then Exit Sub

        Dim cercaForm As IEnumerable(Of XElement) =
                From c In cercaUtente.Elements("Form") Where c.Attribute("name").Value = formToPosition.Name
            Select c

        If cercaForm.Count = 0 Then Exit Sub

        '   Preleva tutti gli attributi
        '
        Dim position As XElement = cercaForm.ElementAt(0).Element("Position")
        Dim top As Integer = CInt(position.Attribute("top"))
        Dim left As Integer = CInt(position.Attribute("left"))
        Dim width As Integer = CInt(position.Attribute("width"))
        Dim height As Integer = CInt(position.Attribute("height"))
        Dim state As FormWindowState = CType([Enum].Parse(GetType(FormWindowState), CStr(position.Attribute("state"))), FormWindowState)

        '   Imposta posizione, dimensione e stato, ma solo se lo stato è normale, altrimenti ignora i valori 
        '
        formToPosition.WindowState = state

        If state = FormWindowState.Normal Then
            formToPosition.Location = New Point(left, top)
            formToPosition.Width = width
            formToPosition.Height = height
            formToPosition.StartPosition = FormStartPosition.Manual
        End If

        '   TODO: controllare che posizione e dimensioni siano NORMALI cioè che la form non vada a finire fuori dallo schermo 

        formToPosition.ResumeLayout(False)
    End Sub