dbml的分部类内的ConnectionString切换

Question

关于Point connectionstring in dbml to app.config

如何将分部类中的连接名称替换为参数，以便切换连接字符串？

Answer 1

如果您使用的是实体框架，则可以使用此类

public static void ChangeDatabase(
        this DbContext source,
        string initialCatalog = "",
        string dataSource = "",
        string userId = "",
        string password = "",
        bool integratedSecuity = true,
        string configConnectionStringName = "",
        string sqlConnectionString = "")
    /* this would be used if the
    *  connectionString name varied from 
    *  the base EF class name */
    {
        try
        {
            // use the const name if it's not null, otherwise
            // using the convention of connection string = EF contextname
            // grab the type name and we're done
            var configNameEf = string.IsNullOrEmpty(configConnectionStringName)
                ? source.GetType().Name
                : configConnectionStringName;

            // add a reference to System.Configuration
            var entityCnxStringBuilder = new EntityConnectionStringBuilder
                (System.Configuration.ConfigurationManager
                    .ConnectionStrings[configNameEf].ConnectionString);

            // init the sqlbuilder with the full EF connectionstring cargo
            var sqlCnxStringBuilder = new SqlConnectionStringBuilder
                (entityCnxStringBuilder.ProviderConnectionString);

            if (string.IsNullOrEmpty(sqlConnectionString))
            {
                // only populate parameters with values if added
                if (!string.IsNullOrEmpty(initialCatalog))
                    sqlCnxStringBuilder.InitialCatalog = initialCatalog;
                if (!string.IsNullOrEmpty(dataSource))
                    sqlCnxStringBuilder.DataSource = dataSource;
                if (!string.IsNullOrEmpty(userId))
                    sqlCnxStringBuilder.UserID = userId;
                if (!string.IsNullOrEmpty(password))
                    sqlCnxStringBuilder.Password = password;

                // set the integrated security status
                sqlCnxStringBuilder.IntegratedSecurity = integratedSecuity;
                sqlConnectionString = sqlCnxStringBuilder.ConnectionString;
            }

            // now flip the properties that were changed
            source.Database.Connection.ConnectionString
                = sqlConnectionString;
        }
        catch (Exception ex)
        {
            // set log item if required
        }
    }

并使用以下命令调用此类

dbContext = new ORM.CustomyzerEntities();
                this._destDBContext.ChangeDatabase(
                    sqlConnectionString: connectionstringname);

在这里将connectionstringname替换为您的连接字符串