# CSharpSample **Repository Path**: maxwell/csharpsample ## Basic Information - **Project Name**: CSharpSample - **Description**: C# 示例代码 - **Primary Language**: C# - **License**: Not specified - **Default Branch**: master - **Homepage**: None - **GVP Project**: No ## Statistics - **Stars**: 14 - **Forks**: 6 - **Created**: 2013-06-07 - **Last Updated**: 2022-12-01 ## Categories & Tags **Categories**: Uncategorized **Tags**: None ## README Sample Queries

Welcome to the C# Samples

Unblocking Folder Links

If you have downloaded these samples from the Internet and the folder links below do not function, you may need to unblock this ReadMe file. Try the following steps:

In Windows Explorer, right-click the ReadMe.html file you loaded to view this page, and click Properties.
Click the Unblock button at the bottom of the property pane, and then click OK.

Language Samples

We have created a set of language samples to help you get familiar with various C# language features. They are available in the LanguageSamples folder.

LINQ Samples

We have created four sets of samples for you that are designed to help you learn LINQ quickly, and to act as a reference and guide for those with more advanced skills. A few handy utilities are also included.

Important: If the folder links below do not function, please follow the instructions above under Unblocking Folder Links.

Getting Started with LINQ

SampleQueries: This is the most important sample and contains about 500 examples of how to use each of the query operators in LINQ to Objects, LINQ to SQL, LINQ to XML and LINQ to DataSet.
SimpleLinqToObjects: The hello world of the LINQ samples. This shows you how easy it is to do simple queries of in-memory objects using LINQ to Objects.
LinqToNorthwind: A basic example of how to use LINQ To SQL to query a database.
SimpleLinqToXml: Get started using LINQ to XML.
WinFormsDataBinding: Learn how to display LINQ queries with grids in a Windows form. It includes a one to many query example.
XQuery: Another simple LINQ to XML sample query. This sample shows the minimal code necessary to write a LINQ to XML query
LinqToXmlDataBinding: Bind LINQ to XML code to WPF controls.

Advanced Samples

DynamicQuery: Code to create LINQ queries at run time.
Reflector: Use LINQ to right queries against the objects in your code using the Reflection APIs.
RSS: This sample acts as a tiny web server that aggregates several RSS feeds
SimpleLambdas: Several examples of how to write and use lambda expressions.
WebServiceLinqProvider: A sample showing how to create a LINQ provider to query Terraserver, a web service offering geographical data.

Addins and Visualizers

ExpressionTreeVisualizer: Create a visualization of an Expression Tree.
QueryVisualizer: Allows LINQ to SQL developers to see the SQL for their query, and also to see the results of the query in a grid.
PasteXmlAsLinq: A Visual Studio addin that automatically converts XML markup to LINQ to XML code. Note: Addins cannot be compiled or loaded within C# Express.

Libraries or Utilities

Data: Contains XML files and a modified copy of the Northwind database for use by several of the other samples.
ObjectDumper: A utility for writing the output from a LINQ query to the screen in text mode.
NorthwindMapping: Contains the ORM mapping created by the LINQ to SQL designer for the Northwind database that ships with these samples. It is used by DynamicQuery and WinFormsDataBinding.
Whitepapers: The following papers are stored in this directory in Word format:
- LINQ Project Overview
- LINQ to SQL Overview for C# and VB
- Standard Query Operators
- LINQ to XML Overview

LINQ Samples Database Connectivity Issues

The default connect string for the samples should work without modification if you have SQL Server Express installed on your development machine. Here is an alternate connect string that you can modify for your own purposes if you are not using SQL Express but have SQL Server available. You will probably need to modify the word test wherever it appears in the sample connect string.

string connString = 
  "server=test;database=northwind;user id=test;password=test";

On some SQL Express installations, you may not have the rights to start a user instance. If you get an error message to that effect, try removing the clause ";user instance = true" from the connection string.

Be sure that the copies of the northwind database that you are accessing are not marked read only. If necessary, browse to the copy of NORTHWIND.MDF you are trying to access, right click on the file, choose properties. Clear the Read-only attribute.

On some slow machines, or when using a virtual pc, users have reported that some database applications give errors the first time they run. Try running the sample two or three times.

The customized copies of the Northwind database included with the samples ship without an LDF (log) file. This is done intentionally, so that the LDF and MDF files do not get out of sync. When you run a sample that uses the database, or attach to the database from the Server Explorer inside Visual Studio, the LDF file will be created automatically. You may have trouble connecting to the MDF file if you are using the SQL Server Management Studio without first creating a log file.