The C# code:

string sql = @"SELECT
CONVERT(VARCHAR, s.street_name) AS street_name,
CONVERT(VARCHAR, mc.management_company_name) AS management_company_name,
CONVERT(VARCHAR, tc.type_constuction_name) AS type_constuction_name,

FROM building_description bd
JOIN street s ON bd.Id_street = s.Id_street
JOIN management_company mc ON bd.Id_management_company = mc.Id_management_company
JOIN type_constuction tc ON bd.Id_type_constuction = tc.Id_type_constuction

“;

```
`using(SqlCommand command = new SqlCommand(sql, connection)) 
 {    
    using(SqlDataReader reader = command.ExecuteReader())    
    {      
        while (reader.Read())      
        {        
            DataInfo dataInfo = new()        
            {          
                Street =  reader.GetString(reader.GetOrdinal("street_name")),
                Type_constuction = reader.GetString(reader.GetOrdinal("type_constuction_name")),
                Management_company_name =  reader.GetString(reader.GetOrdinal("management_company_name")),     
            };        
            DataList.Add(dataInfo);      
        }    
    } 
```
 }`

`#The error:#

Exception thrown: ‘System.InvalidCastException’ in Microsoft.Data.SqlClient.dll
Unable to cast object of type ‘System.String’ to type ‘System.Int32’.

I expected that when the browser starts, a table appears with data from the building_description table

if you just display the table, the browser shows the table
string sql = “SELECT * FROM building_description;”;

maybe I’m missing the point where I replace the values to output the table to the browser or I have a mismatch in the index where the row is located in the database table