Question

我有在app.config中更改连接字符串的代码。但是当我更改数据库时遇到错误，因为linq to sql.dbml没有更新到我改变的数据库。 我需要关闭程序并再次打开以实现更改。我该怎么做才能将我的linq更新为sql.dbml？

var name = "DbName";
   bool isNew = false;
            string path = AppDomain.CurrentDomain.SetupInformation.ConfigurationFile;
            XmlDocument doc = new XmlDocument();
            doc.Load(path);
            XmlNodeList list = doc.DocumentElement.SelectNodes(string.Format("connectionStrings/add[@name='{0}']", name));
            XmlNode node;
            isNew = list.Count == 0;
            if (isNew)
            {
                node = doc.CreateNode(XmlNodeType.Element, "add", null);
                XmlAttribute attribute = doc.CreateAttribute("name");
                attribute.Value = name;
                node.Attributes.Append(attribute);

                attribute = doc.CreateAttribute("connectionString");
                attribute.Value = "";
                node.Attributes.Append(attribute);

                attribute = doc.CreateAttribute("providerName");
                attribute.Value = "System.Data.SqlClient";
                node.Attributes.Append(attribute);
            }
            else
            {
                node = list[0];
            }
            string conString = node.Attributes["connectionString"].Value;
            SqlConnectionStringBuilder conStringBuilder = new SqlConnectionStringBuilder(conString);
            conStringBuilder.DataSource = txtConnectServername.Text;
            conStringBuilder.InitialCatalog = "AlTayerDB";
            conStringBuilder.PersistSecurityInfo = true;
            conStringBuilder.UserID = txtConnectUserId.Text;
            conStringBuilder.Password = txtConnectAdapterPassword.Text;
            conStringBuilder.MultipleActiveResultSets = true;
            node.Attributes["connectionString"].Value = conStringBuilder.ConnectionString;
            if (isNew)
            {
                doc.DocumentElement.SelectNodes("connectionStrings")[0].AppendChild(node);
            }
            doc.Save(path);

Answer 1

我建议您按照此处 - How do I (update/insert/remove) the config file during runtime?获取有关此主题的完整信息：

在运行时修改配置文件中的现有值。

由于Configuration.AppSettings属性是只读的，为了修改当前的应用程序设置值，我们必须使用XmlDocument类将应用程序配置文件直接更新为XML文档。

这是原始的App.config文件：

<configuration>
  <appSettings>
    <add key="Setting1" value="1" />
    <add key="Setting2" value="2" />
  </appSettings>
</configuration>

以下是修改应用程序设置值的代码示例：

XmlDocument xmlDoc = new XmlDocument();

xmlDoc.Load(AppDomain.CurrentDomain.SetupInformation.ConfigurationFile);

foreach (XmlElement element in xmlDoc.DocumentElement)
{
    if (element.Name.Equals("appSettings"))
    {
        foreach (XmlNode node in element.ChildNodes)
        {
            if (node.Attributes[0].Value.Equals("Setting1"))
            {
                node.Attributes[1].Value = "New Value";
            }
        }
    }
}

xmlDoc.Save(AppDomain.CurrentDomain.SetupInformation.ConfigurationFile);

ConfigurationManager.RefreshSection("appSettings");

如果这不符合要求，请检查以下参考文献：
Change the value in app.config file dynamically
App.Config change value
update app.config file programatically with ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);

如何动态更改数据库连接时如何更新LINQ to SQL.dbml

1 个答案: