Question

如果连接字符串没有退出，我尝试创建连接字符串。然后必须创建一个新的连接字符串。我这样试试：

internal static string Search(string data, string customerSchema)
        {
            string result = String.Empty;

            // get search string from the data
            XDocument doc = XDocument.Parse(data);
            XElement el = doc.Root.Element("search");
            if (el == null || String.IsNullOrWhiteSpace(el.Value))
                return ConstructFaultResponse("No search parameter found", String.Empty);

                       // var config = ConfigurationManager.OpenExeConfiguration(DbSchema.ConnectionNameSuffix);
                        var zipcodeConnection = ConfigurationManager.ConnectionStrings[DbSchema.Sfs];
                    if (zipcodeConnection == null) {
                            System.Configuration.ConfigurationManager.ConnectionStrings.Add(new ConnectionStringSettings {
                        Name = DbSchema.Sfs,
                        ConnectionString = zipcodeConnection.ConnectionString,
                        ProviderName = "System.Data.SqlClient" //Depends on the provider, this is for SQL Server
                    });



                    }


            if (zipcodeConnection != null) {
                try {
                    using (SqlConnection conn = new SqlConnection(zipcodeConnection.ConnectionString)) {
                        if (el.Value.Length > 6) {
                            conn.Open();
                            using (SqlCommand cmd = new SqlCommand(@"select top 1 s.street, s.town 
    from streets s 
    join Addresses a on a.streetid=s.id
    where a.zipcode=@zip and a.HouseNumber=@nr", conn)) {
                                cmd.Parameters.AddWithValue("zip", el.Value.Substring(0, 6));
                                cmd.Parameters.AddWithValue("nr", el.Value.Substring(6));
                                using (SqlDataReader reader = cmd.ExecuteReader()) {
                                    if (reader.Read()) {
                                        XElement xResponse = new XElement("response",
                                            new XElement("straatnaam", reader.GetString(0)),
                                            new XElement("plaatsnaam", reader.GetString(1))
                                        );
                                        return xResponse.ToString();
                                    }

                                }
                            }
                        }
                    }
                    return ConstructFaultResponse("Unknown address", "unknown_address");
                }
                catch (Exception e) {
                    return ConstructFaultResponse(e.Message, "BAG_Zipcode_error");
                }
            }

但问题出在这段代码之后：

if (zipcodeConnection == null) {
                            System.Configuration.ConfigurationManager.ConnectionStrings.Add(new ConnectionStringSettings {
                        Name = DbSchema.Sfs,
                        ConnectionString = zipcodeConnection.ConnectionString,
                        ProviderName = "System.Data.SqlClient" //Depends on the provider, this is for SQL Server
                    });

它不会跳到这个：

if (zipcodeConnection != null) {

谢谢

Oke，我改为：

 var zipcodeConnection = ConfigurationManager.ConnectionStrings["BAG_Zipcodes"];

            if (zipcodeConnection == ConfigurationManager.ConnectionStrings["BAG_Zipcodes"])
                zipcodeConnection = ConfigurationManager.ConnectionStrings["BAG_Zipcodes"];

            else if (zipcodeConnection != ConfigurationManager.ConnectionStrings["BAG_Zipcodes"]) {
                zipcodeConnection = ConfigurationManager.ConnectionStrings[DbSchema.DefaultConnectionName];
            }

但它永远不会出现在这个问题上：

else if (zipcodeConnection != ConfigurationManager.ConnectionStrings["BAG_Zipcodes"]) {
                zipcodeConnection = ConfigurationManager.ConnectionStrings[DbSchema.DefaultConnectionName];
            }

谢谢

我有这样的连接字符串：

  <add name="BAG_Zipcodes" connectionString="Password=;Persist Security Info=True;User ID=sa;Initial Catalog=e;Data Source=" />

因此，如果它在webconfig中具有该连接字符串，则使用该连接字符串。否则使用：

  zipcodeConnection = ConfigurationManager.ConnectionStrings[DbSchema.DefaultConnectionName];

Answer 1

您的zipcodeConnection从未设置过值，因此它仍然为空。

你不需要像你一样检查声明是否两次。我建议就这样做

                    if (zipcodeConnection == null) 
                    {
                        // Set the zipCodeConnection's value
                    }

                    try {
                            using (...) {
                                         }
                        }

在此处回答您的编辑问题：

因为您的zipcodeConnection始终是

zipcodeConnection == ConfigurationManager.ConnectionStrings["BAG_Zipcodes"]

这就是为什么它总是跳过

if (zipcodeConnection != ConfigurationManager.ConnectionStrings["BAG_Zipcodes"])

Answer 2

我这样解决了：

 var zipcodeConnection = ConfigurationManager.ConnectionStrings["BAG_Zipcodes"];
            zipcodeConnection = ConfigurationManager.ConnectionStrings[DbSchema.DefaultConnectionName];

            if (zipcodeConnection == ConfigurationManager.ConnectionStrings["BAG_Zipcodes"])
                zipcodeConnection = ConfigurationManager.ConnectionStrings["BAG_Zipcodes"];

            if (zipcodeConnection == ConfigurationManager.ConnectionStrings[DbSchema.DefaultConnectionName]) 
                zipcodeConnection = ConfigurationManager.ConnectionStrings[DbSchema.DefaultConnectionName];

但它可以简明扼要吗？

谢谢

Answer 3

我不确定你要做什么但是我建议你尝试设置zipcodeConnectionString如果它为null所以你需要做这样的事情

var zipcodeConnection = ConfigurationManager.ConnectionStrings[DbSchema.DefaultConnectionName];
if (zipcodeConnection == null)
{
   zipcodeConnection = ConfigurationManager.ConnectionStrings["BAG_Zipcodes"]
}

如果不退出，则创建连接字符串

3 个答案: