Question

Cannot implicitly convert type 'System.Collections.Generic.List<string>'
to 'System.Collections.Generic.List<Parts>'

Below is the code generating this error. I am pretty sure I am doing something silly.

public class Parts
{


public string computername { get; set; }


public List<Parts> GetParts()
{
    List<string> lst = new List<string>(); 
   //The object that will physically connect to the database 
   using(SqlConnection cnx = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["request"].ConnectionString))  
   { 
            //The SQL you want to execute 
       SqlCommand cmd = new SqlCommand("SELECT * FROM REQUESTS", cnx); 
           //Open the connection to the database 
           cnx.Open(); 
           //execute your command 
           SqlDataReader dataReader = cmd.ExecuteReader(); 
           { 
             //Loop through your results 
             while(dataReader.Read()) 
             { 
                lst.Add(Convert.ToString(dataReader["titlename"])); 
             } 
           } 
   } 
   return lst; 
} 

}

The error keeps pointing to this line:

   return lst; 

Thank you

Answer 1

The return type of method GetParts() is List<Parts>, but in function, you try to return a List<string>

try this:

public List<Parts> GetParts()
{
    List<Parts> lst = new List<Parts>(); 
    using (SqlConnection cnx = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["request"].ConnectionString))
    {
        SqlCommand cmd = new SqlCommand("SELECT * FROM REQUESTS", cnx);
        cnx.Open();
        Parts parts = null; 
        SqlDataReader dataReader = cmd.ExecuteReader();
        { 
            while (dataReader.Read())
            {
                parts = new Parts();
                parts.computername = dataReader["titlename"].ToString();
                lst.Add(parts);
            }
        }
    }
    return lst;
} 

public void SomeMethod(List<Parts> parts)
{
    List<string> title = new List<string>();
    foreach(var item in parts)
    {
        title.Add(item.titlename);
    }
    this.ddlPartsTitle.Datasource = title;
    this.ddlPartsTitle.DataBind();
}

public YourClassName()
{
    this.SomeMethod(this.GetParts());
}