Microsoft Visual Studio .NET 2008 Tips

1. Using Linq

1. Use Server Explorer to connect to a SQL Server
2. Drag the table to your dbml diagram
3. Open projectname.designer.cs under projectname.dbml and search for the table name
Linq has generated the methods for select, insert, update and delete operations which will be called in the consumer classes.

4. Add a new class e.g. ProductAttributes.cs
5. Add the following to the new class

Note: example using get and set methods.
The retrieve function could build a dynamic object list or set simple variables.


private string attribute1;
private string attribute2;
private string attribute3;

public string Attribute1
{
    get { return attribute1; }
    set { attribute1 = value; }
}

public string Attribute2
{
    get { return attribute2; }
    set { attribute2 = value; }
}

public string Attribute3
{
    get { return attribute3; }
    set { attribute3 = value; }
}

String sz = System.Configuration.ConfigurationManager.ConnectionStrings["Project1AppConnectionString"].ToString();
public void Retrieve(int id)
{
    Project1DataContext db = new Project1DataContext(sz);
    var attributesRecs = db.sproc_t_attributes_valuesSelect(id);

    foreach (var attribute in attributesRecs)
    {
        attribute1 = attribute.Attribute1_Value;
        attribute2 = attribute.Attribute2_Value;
        attribute3 = attribute.Attribute3_Value;
    }
}

public void Create()
{

}

public void Update()
{

}

public void Delete()
{

}

Update the Create, Update and Delete methods to use the correct functions in projectname.designer.cs under projectname.dbml in Solution Explorer.

Call from a test harness.
Add a project reference to the data access component.


protected void GetProductAttributes_Click(object sender, EventArgs e)
{
    ProductAttributes x = new ProductAttributes();
    x.Retrieve(1);
    Response.Write(x.Attribute1 + "<br />");
    Response.Write(x.Attribute2 + "<br />");
    Response.Write(x.Attribute3 + "<br />");
}

2. New namespaces

Data access provider.


using System;
using System.Data;
using System.Configuration;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Collections.Generic;
using System.ComponentModel;

In a test harness the following namespaces must be added for the example above.


using System.ComponentModel;
using Project1;

3. Accessing output parameters from stored procedure calls

Data access provider.


private int table1ID;

public int Create()
{
    Project1DataContext db = new Project1DataContext(sz);
    System.Data.Linq.ISingleResult<sproc_t_table1Insert> r = db.sproc_t_table1Insert(name, description, DateTime.Now);
    int nRet = (int)r.ReturnValue;
    table1ID = (int)r.ElementAt(0).table1ID;
    return nRet;
}

table1ID = (int)r.ElementAt(0).table1ID uses the Enumerable object to access the generated return output variables.

4. Lambdas

A lambda expression is an anonymous function that you can use to create delegates or expression tree types. A delegate is a type that safely encapsulates a method, similar to a function pointer in C and C++. They are necessary for Linq.
The types of lambdas available in C# are:
Expression Lambdas, Statement Lambdas, Async Lambdas and Lambdas with Standard Query Operators.
The lambda operator is => and you put the expression or statement block on the other side.
Example:


delegate int del(int i);
...
del myDelegate = x => x * x;
int j = myDelegate(5); //j = 25

5. WPF (Windows Presentation Foundation) and WCF (Windows Communication Foundation)

WPF can be run in a browser, and SilverLight is a subset of WPF. WCF can be used in ASP.NET applications. It should be an improved version of asmx web services but I have never been asked to use it. People want restful WebApps using JSON and responive UIs. Not XAML.

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