我无法使用连接字符串连接数据库

Question

I am a beginner in Visual Studio and in using SQL Server databases. I have connected my SQL Server database in Server Explorer and tested the connection; it connected successfully.

Now I have a problem adding a row in the database using the Visual Studio coding. I don't know how to connect to that SQL Server database using that connection string. I am posting the images for the same. This is the image with the coding I had used, the Text line which is coloured is

(
    cnn.ConnectionString =
        System.Configuration.ConfigurationManager.ConnectionStrings[
            "Data Source=(LocalDb)\v11.0;Initial Catalog=aspnet-WebApplication5-20160919115911;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|\aspnet-WebApplication5-20160919115911.mdf "
        ].ConnectionString;
)

My web.config screen shot is like this.

The text in the connection string is

(    <add name="DefaultConnection" providerName="System.Data.SqlClient" connectionString="Data Source=(LocalDb)\v11.0;Initial Catalog=aspnet-WebApplication5-20160919115911;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|\aspnet-WebApplication5-20160919115911.mdf" /> )

Please guide me what to do.

I had made the database on localhost .

Answer 1

您必须传递配置条目的名称（在本例中为DefaultConnection才能从配置文件中获取它，而不是从连接字符串本身获取，因此正确的代码是这样

cnn.ConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings["DefaultConnection"];

Answer 2

ConnectionStrings takes the name , not the entire string.

So correct code is cnn.ConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings["name"];

Answer 3

The connectionString must be include in appconfig or webconfig (config File)

Set ConnectionString

<configuration>
    <connectionStrings>
        <add name="ConStr" connectionString="Data Source=.;Initial Catalog=balbla;IntegratedSecurity=True" providerName="System.Data.SqlClient" />
    </connectionStrings>
</configuration>

GetConnectionString :

cnn.ConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings["ConStr"].ConnectionString;