在 ADO.NET（包装类）中编写更少的代码

Question

So I'm pretty new to C# in general, but I have a basic knowledge of the language at the moment.

When accessing an SQL database, I've decided that using ADO.NET (SqlClient seems to be the best way to do it, and I have managed to get it working, including using queries. My issue is that as soon as I start to query the database more often, I seem to just be rewriting very similar code over and over again (which is obviously bad practice). It's clear that I need to make some sort of class that handles my use of ADO.NET (SqlClient) so that I cant just type something like the following:

DatabaseConnection.Query("SELECT * FROM tblProducts");

… instead of...

using (SqlConnection cnn = new SqlConnection(cnnString)) // cnnString was defined earlier in the code
{
    SqlCommand cmd = new SqlCommand("SELECT ProductType FROM tblProductTypes", cnn);
    DataTable dt = new DataTable();
    cnn.Open();
    dt.Load(cmd.ExecuteReader());
    cboFilterTypes.DataSource = dt;
    cboFilterTypes.DisplayMember = "ProductType";
    cboFilterTypes.ValueMember = "ProductType";
    cnn.Close();
}

So I think I need to make a class wrapper (at least that's what I believe it is called), but I'm not too sure on how to go about doing it. Does anyone have any suggestions or tricks that I can use?

To be clear, I am not wanting to use the entity framework or anything like that which is built on ADO.NET - I've tried to entity framework and have decided there are too many drawbacks.

Answer 1

Sticking with your request for a 'wrapper' you could simply make a static helper method to handle the call to the database such as

    public static DataTable GetDataTable(string query)
    {
        DataTable result = new DataTable();
    using (SqlConnection cnn = new SqlConnection(cnnString)) // cnnString was defined earlier in the code
    {
            SqlCommand cmd = new SqlCommand(query, cnn);
            result = new DataTable();
            cnn.Open();
            result.Load(cmd.ExecuteReader());
            cnn.Close();
     }
return result;
    }

You could then call this like

    cboFilterTypes.DataSource = GetDataTable("SELECT ProductType FROM tblProductTypes")
    cboFilterTypes.DisplayMember = "ProductType";
    cboFilterTypes.ValueMember = "ProductType";

I wouldn't recommend this way of data access for anythig other than a tiny project. If you really don't like EF then Dapper or something similar offers a much more scalable solution. Stackoverflow itself uses Dapper:)