用变量修改连接字符串 [英] Modifying connection string with variables

问题描述

所以我的目标是要有一个设置表单，允许用户编辑连接字符串（通过更改数据库名称/服务器位置。）

so my goal is to have a "settings form" which allows users to edit the connection string (by changing the database name / server location.

这是因为它可能需要在没有任何C＃经验的人（前端GUI）不久之后更改服务器位置时进行更改。

The reason for this is that it it needs to be able to changed when the server locations changes shortly by someone who may not have any C# experience (Front-End GUI).

I'在app.config中创建了连接字符串，但找不到在conn字符串中分配可以更改的变量的方法？我已经使用项目属性创建了一些应用程序范围的设置，这就是我的app.config

I've created the connection strings in app.config but cannot find a way to assign variables inside the conn string that can be changed? I've created some application wide settings using the project properties. This is my app.config

<connectionStrings>
    <add name="xxxx"
        connectionString="Data Source=ServerIP;Initial Catalog=DBName;Persist Security Info=True;User ID=user;Password=password"
        providerName="System.Data.SqlClient" />
</connectionStrings>
<applicationSettings>
    <xxx.Properties.Settings>
        <setting name="ServerIP" serializeAs="String">
            <value />
        </setting>
        <setting name="DBName" serializeAs="String">
            <value />
        </setting>
    </xxx.Properties.Settings>
</applicationSettings>

推荐答案

一种实现此目的的方法是使用占位符（ {0} 和 {1} ），用于配置文件中连接字符串的那些部分，如下所示：

One way to accomplish this would be to use placeholders ({0} and {1}) for those parts of the connection string in the config file, like so:

Data Source={0};Initial Catalog={1};Persist Security Info=True;User ID=user;Password=password

然后通过 string.Format 当您在代码中读取连接字符串时，如以下示例所示。 （注意：这假定您已添加对 System.Configuration.dll 的引用，并且已将应用程序设置检索到两个变量 serverIP 和 dbName 。）

And then fill them in via string.Format when you read the connection string in your code, as in the following example. (Note: This assumes that you've added a reference to System.Configuration.dll, and that you've retrieved the application settings into two variables, serverIP and dbName.)

using System.Configuration;

...

string connectionString = string.Format(
    ConfigurationManager.ConnectionStrings["xxxx"].ConnectionString,
    serverIP,
    dbName);

这篇关于用变量修改连接字符串的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！