How do I retrieve data from a database into a class library object

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I'm trying to get data from my database to a class library object, I'm using a stored procedure and dapper, my query works alright but what I need is to retrieve data from a particular table into my class library object, any ideas please?

What I have tried:

Public class sqlconnector IDataConnection:
Public TransactionsModel GetStockQuantity (TransactionsModel modell)
{
List<Transactions Model> output;
Using(IDbConnection connection= new MySqlConnection(GlobalConfig.CnnString(mydb)))
{
output = connection.Query<TransactionsModel>("Book_GetAll_By_BookTitle",new {book_titlesp=model.Transacted_book_name}, command type: CommandType.StoredProcedure).ToList();
var p= new DynamicParameter();
modell.QuantityAgain= p.Get<int>("quantity").ToString();
}
return model.MyQuantity;
}

The model.transacted book name gets into the query but it does give the output
When I run it it gives the exception system.collection.generic.key not found exception,the given key was not present in the dictionary at the command

Modell.QuantityAgain= p.Get<int>("quantity").ToString();

Posted 25-May-20 7:14am

Tobynate

Updated 27-May-20 8:23am

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Comments

Maciej Los 26-May-20 2:16am

What collation?

2 solutions

Solution 1

Please, read this:
mysql - System.Collections.Generic.KeyNotFoundException: 'The given key was not present in the dictionary.' C# windows application - Stack Overflow[^]
c# - .Net MySql error "The given key was not present in the dictionary" - Stack Overflow[^]
How to fix System.Collections.Generic.KeyNotFoundException "The given key was not present in the dictionary" Excepiton with MySQL Connector/NET and utf8mb4 character set - Sysadmins of the North[^]

Posted 25-May-20 20:20pm

Maciej Los

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Richard Deeming · Accepted Answer · 2020-05-27T08:24:00

Quote:

C#

var p= new DynamicParameter();
modell.QuantityAgain= p.Get<int>("quantity").ToString();

It's hardly surprising that Get fails, given that you've literally just created the DynamicParameters object, and haven't added any parameters to it!

Compare your code to the example in the documentation:
GitHub - StackExchange/Dapper: Dapper - a simple object mapper for .Net[^]

C#

public int GetStockQuantity(TransactionsModel model)
{
    using (IDbConnection connection= new MySqlConnection(GlobalConfig.CnnString(mydb)))
    {
        var p = new DynamicParameter();
        p.Add("@book_titlesp", model.Transacted_book_name);
        p.Add("@quantity", dbType: DbType.Int32, direction: ParameterDirection.Output);
        
        connection.Execute("Book_GetAll_By_BookTitle", p, commandType: CommandType.StoredProcedure);
        
        return p.Get<int>("@quantity");
    }
}

How do I retrieve data from a database into a class library object

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How do I retrieve data from a database into a class library object

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