将动态连接字符串写入 XML 文件答案

【问题标题】：Write Dynamic Connection String to XML file将动态连接字符串写入 XML 文件
【发布时间】：2019-08-20 08:56:49
【问题描述】：

我希望将我的动态 SQL 连接字符串保存到 XML 文件中。下面是我将连接字符串保存到 SQLSettings.Dat 文件的代码。

我想要，它也应该保存到 XML 文件中，比如 App.config 文件。

Public Sub dbConnection()
    If File.Exists(Application.StartupPath & "\SQLSettings.dat") Then
        Dim quoteArray As String() = File.ReadAllLines(Application.StartupPath & "\SQLSettings.dat")
        For Each Item As String In quoteArray
            connstring = $"Data Source={quoteArray(0)};Initial Catalog={quoteArray(1)};User ID={quoteArray(2)};pwd={quoteArray(3)};"
        Next
    Else
        MsgBox("Database settings not exists, save settings before!")
        frmDBSettings.ShowDialog()
        Application.Restart()
    End If
    Try
        conn = New SqlConnection
        conn.ConnectionString = connstring
        conn.Open()
    Catch ex As SqlException
        MsgBox(ex.Message)
    End Try
End Sub

【问题讨论】：

标签： sql xml vb.net

【解决方案1】：

尝试以下 xml linq

Imports System.IO
Imports System.Xml
Imports System.Xml.Linq
Imports System.Data.SqlClient

Public Class Form1
    Const FILENAME As String = "c:\temp\test.xml"
    Public Sub dbConnection()
        Dim xmlHeader As String = "<?xml version=""1.0"" encoding=""utf-8"" ?><ConnectionStrings></ConnectionStrings>"

        Dim doc As XDocument = XDocument.Parse(xmlHeader)
        Dim connectionStrings As XElement = doc.Root
        Dim connstring As String

        If File.Exists(Application.StartupPath & "\SQLSettings.dat") Then
            Dim quoteArray As String() = File.ReadAllLines(Application.StartupPath & "\SQLSettings.dat")
            For Each Item As String In quoteArray
                'Console.WriteLine(Item)
                connstring = $"Data Source={quoteArray(0)};Initial Catalog={quoteArray(1)};User ID={quoteArray(2)};pwd={quoteArray(3)};"
                Dim connectionString As New XElement("ConnectionString", connstring)
                connectionStrings.Add(connectionString)
            Next
            doc.Save(FILENAME)
        Else
            MsgBox("Database settings not exists, save settings before!")
            frmDBSettings.ShowDialog()
            Application.Restart()
        End If

        Try
            conn = New SqlConnection
            conn.ConnectionString = connstring
            conn.Open()
        Catch ex As SqlException
            MsgBox(ex.Message)
        End Try
    End Sub
End Class

【讨论】：

它工作得很好，感谢刚刚更改了一个bi，将这些行移到循环之外 Dim connectionString As New XElement("ConnectionString", connstring) connectionStrings.Add(connectionString)
你需要在 For 循环中使用它，否则你只会得到一个结果（最后一个）。