System.NotSupportedException错误修复：连接我的文档中LocalDB数据库

原代码 #

string dbPath = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
dbPath = Path.Combine(dbPath, "Database1.mdf");
cn = new SqlConnection (@"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=|DataDirectory| "+dbPath+";Integrated Security=True");
GetAllRecords();

运行时错误 #

System.NotSupportedException: 'The given path's format is not supported.'

问题分析 #

连接字符串中同时混用了|DataDirectory|占位符和完整物理路径dbPath，生成了类似|DataDirectory| C:\Users\XXX\Documents\Database1.mdf的无效路径格式，LocalDB无法识别这种混合写法。

修复方案 #

直接移除连接字符串中的|DataDirectory| ，使用已拼接好的完整物理路径即可。推荐用字符串插值构建连接字符串，避免拼接时的空格或格式问题：

string dbPath = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
dbPath = Path.Combine(dbPath, "Database1.mdf");
// 使用字符串插值构建连接字符串，格式更清晰
cn = new SqlConnection($"Data Source=(LocalDB)\\MSSQLLocalDB;AttachDbFilename={dbPath};Integrated Security=True");
GetAllRecords();

如果偏好传统字符串拼接写法，修正后的代码如下：

string dbPath = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
dbPath = Path.Combine(dbPath, "Database1.mdf");
cn = new SqlConnection(@"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=" + dbPath + ";Integrated Security=True");
GetAllRecords();

内容的提问来源于stack exchange，提问作者Shashika Lakshan