来自： http://www.yaosansi.com/post/1380.html
记录LINQ生成的SQL语句是常用的调试方式,而且能根据需要来优化LINQ生成的SQL语句,更能了深入的了解LINQ.
DataContext的Log属性来将LINQ to SQL生成的SQL语句格式化.
一.控制台程序(Console)
dataContext.Log = Console.Out;
二.利用GetCommand方法
dataContext.GetCommand(query).CommandText;
三.使用LINQPad ( 官方网站 )
LINQPad支持C# 3.0 和 Framework 3.5的全部功能：
- LINQ to SQL
- LINQ to Objects
- LINQ to XML
更多介绍请参考 李永京 的 学习LINQ工具：LINQPad
下载地址: http://www.albahari.com/LINQPad.exe
四.LINQ to SQL Debug Visualizer
ScottGu的LINQ to SQL Debug Visualizer可以在Debug过程中查看SQL语句.
介绍: http://weblogs.asp.net/scottgu/archive/2007/07/31/linq-to-sql-debug-visualizer.aspx
下载: http://www.scottgu.com/blogposts/linqquery/SqlServerQueryVisualizer.zip
安装方法
1. 关闭 VS2008。
2. 将压缩包中的 SqlServerQueryVisualizer.dll 拷贝到 \Program Files\Microsoft Visual Studio 9.0\Common7\Packages\Debugger\Visualizers。
3. 重启 VS2008 即可。
五.DebuggerWriter工具类
由于Console.Out方法在ASP.NET程序不起作用.
Kris Vandermotten 已经创建好了一个这个工具类, 你只要使用这样的语法:
MyDataContext db =
new
MyDataContext();
db.Log =
new
DebuggerWriter();
asp.net可以选择将Log信息直接发送到Debug的输出窗口.
源码:
using
System;
using
System.Diagnostics;
using
System.Globalization;
using
System.IO;
using
System.Text;
namespace
Vandermotten.Diagnostics
{
///
<summary>
///
Implements a
<see cref="TextWriter"/>
for writing information to the debugger log.
///
</summary>
///
<seealso cref="Debugger.Log"/>
public
class
DebuggerWriter : TextWriter
{
private
bool
isOpen;
private
static
UnicodeEncoding encoding;
private
readonly
int
level;
private
readonly
string
category;
///
<summary>
///
Initializes a new instance of the
<see cref="DebuggerWriter"/>
class.
///
</summary>
public
DebuggerWriter()
:
this
(
0
, Debugger.DefaultCategory)
{
}
///
<summary>
///
Initializes a new instance of the
<see cref="DebuggerWriter"/>
class with the specified level and category.
///
</summary>
///
<param name="level">
A description of the importance of the messages.
</param>
///
<param name="category">
The category of the messages.
</param>
public
DebuggerWriter(
int
level,
string
category)
:
this
(level, category, CultureInfo.CurrentCulture)
{
}
///
<summary>
///
Initializes a new instance of the
<see cref="DebuggerWriter"/>
class with the specified level, category and format provider.
///
</summary>
///
<param name="level">
A description of the importance of the messages.
</param>
///
<param name="category">
The category of the messages.
</param>
///
<param name="formatProvider">
An
<see cref="IFormatProvider"/>
object that controls formatting.
</param>
public
DebuggerWriter(
int
level,
string
category, IFormatProvider formatProvider)
:
base
(formatProvider)
{
this
.level
=
level;
this
.category
=
category;
this
.isOpen
=
true
;
}
protected
override
void
Dispose(
bool
disposing)
{
isOpen
=
false
;
base
.Dispose(disposing);
}
public
override
void
Write(
char
value)
{
if
(
!
isOpen)
{
throw
new
ObjectDisposedException(
null
);
}
Debugger.Log(level, category, value.ToString());
}
public
override
void
Write(
string
value)
{
if
(
!
isOpen)
{
throw
new
ObjectDisposedException(
null
);
}
if
(value
!=
null
)
{
Debugger.Log(level, category, value);
}
}
public
override
void
Write(
char
[] buffer,
int
index,
int
count)
{
if
(
!
isOpen)
{
throw
new
ObjectDisposedException(
null
);
}
if
(buffer
==
null
||
index
<
0
||
count
<
0
||
buffer.Length
-
index
<
count)
{
base
.Write(buffer, index, count);
//
delegate throw exception to base class
}
Debugger.Log(level, category,
new
string
(buffer, index, count));
}
public
override
Encoding Encoding
{
get
{
if
(encoding
==
null
)
{
encoding
=
new
UnicodeEncoding(
false
,
false
);
}
return
encoding;
}
}
public
int
Level
{
get
{
return
level; }
}
public
string
Category
{
get
{
return
category; }
}
}
}
六.将LINQ to SQL生成的SQL语句写入日志文件
DataContext.Log是System.IO.TextWriter类型,所以你可以用以下的方法来做.
StreamWriter sw =
new
StreamWriter(
Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop),
"log.txt"
));
dBLinqDataContext.Log = sw;
var query = dataContext.Customers.Single<Customer>(c=>c.CustomerID.Contains(
"s"
))
.Skip(0).Take(10).ToList();
sw.Flush();
sw.Close();
但以上方法有个缺点,就是需要在每个实现的方法中都写这么多代码.使用起来太不方便.参照dataContext.Log = Console.Out的表现形式
由是有了FileLog类.(当然,FileLog类除了此功能还有一些基本的记录日志的方法)
使用时直接dataContext.Log = Yaosansi.IO.FileLog.Out;即可. 默认会在桌面上生成一个名叫UnNameFile.txt的文件.
当然如果你不想使用默认的文件名和路径也可以使用dataContext.Log =new Yaosansi.IO.FileLog("FileName")的方式.
下面是FileLog类的源码:
//
原文:
http://www.yaosansi.com/post/1380.html
using
System;
using
System.Collections.Generic;
using
System.Text;
using
System.IO;
namespace
Yaosansi.IO
{
///
<summary>
///
文件操作
///
</summary>
public
class
FileLog : TextWriter
{
构造函数
重写TextWriter
属性
方法
}
}
