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无法将类型“ibatisnet.datamapper.isqlmapper”隐式转换为“ibatisnet.datamapper.sqlmapper”。

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无法将类型“ibatisnet.datamapper.isqlmapper”隐式转换为“ibatisnet.datamapper.sqlmapper”。[已结贴,结贴人:a_sha]

发表于：2007-02-05 11:32:18 楼主

用editplus整理编辑完ibatisnet官网的例子tutorial-1.2.1，使用ibatisnet.datamapper-bin-1.5.1类库。编译命令如下：
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csc /r:../bin/ibatisnet.datamapper.dll /r:../bin/nunit.framework.dll /r:../bin/ibatisnet.common.dll /target:library /out:ibatistutorial.model.dll *.cs
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错误内容:
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无法将类型“ibatisnet.datamapper.isqlmapper”隐式转换为“ibatisnet.datamapper.sqlmapper”。
存在一个显式转换（是否缺少强制转换?)

---------------------------------------------------------
源码如下:

helper.cs
---------------------------------------------
using ibatisnet.datamapper;

namespace ibatistutorial.model
{
/// <summary>
/// base class for helper objects （*helper).
/// provides shared utility methods.
/// </summary>
public abstract class helper
{
public sqlmapper mapper （)
{
return ibatisnet.datamapper.mapper.instance （);
}
}
}
------------------------------------
personhelper.cs
------------------------------------
using system.collections;

namespace ibatistutorial.model
{
/// <summary>
/// helper class for person entities.
/// </summary>
public class personhelper : helper
{
public person select （int id)
{
return （person) mapper （).queryforobject （ "select ", id);
}

public ilist selectall （)
{
return mapper （).queryforlist （ "select ", null);
}

public int insert （person person)
{
mapper （).insert （ "insert ", person);
// insert is designed so that it can return the new key
// but we are not utilizing that feature here
return 1;
}

public int update （person person)
{
return mapper （).update （ "update ", person);
}

public int delete （int id)
{
return mapper （).delete （ "delete ", id);
}

}
}
------------------------------------
helpers.cs
------------------------------------
namespace ibatistutorial.model
{
/// <summary>
/// singleton "controller " for helper classes.
/// </summary>
public class helpers
{
private static volatile personhelper _personhelper = null;

public static personhelper person （)
{
if （_personhelper == null)
{
lock （typeof （personhelper))
{
if （_personhelper == null) // double-check
_personhelper = new personhelper （);
}
}
return _personhelper;
}
}
}
------------------------------------
person.cs
------------------------------------
using system;

namespace ibatistutorial.model
{

/// <summary>
/// business object representing a person
/// entity in our problem domain.
/// </summary>
public class person
{
/*
private string _property;
public string property
{
get { return _property; }
set { _property = value; }
}
*/

private int _id;
public int id
{
get { return _id; }
set { _id = value; }
}

private string _firstname;
public string firstname
{
get { return _firstname; }
set { _firstname = value; }
}

private string _lastname;
public string lastname
{
get { return _lastname; }
set { _lastname = value; }
}

private datetime _birthdate;
public datetime birthdate
{
get { return _birthdate; }
set { _birthdate = value; }
}

private double _weightinkilograms;
public double weightinkilograms
{
get { return _weightinkilograms; }
set { _weightinkilograms = value; }
}

private double _heightinmeters;
public double heightinmeters
{
get { return _heightinmeters; }
set { _heightinmeters = value; }
}

}
}
------------------------------------
请各位大虾帮帮忙。小弟感激不尽！
------------------------------------
------------------------------------

发表于：2007-02-05 12:47:401楼得分:0

帮lz顶

http://user.qzone.qq.com/31767702

发表于：2007-02-05 14:03:132楼得分:20

return ibatisnet.datamapper.mapper.instance （);
应该是这里的问题吧。mapper 属性是sqlmapper类型的，你查一下 instance （)返回的类型，应该是一个接口类型isqlmapper，把这句改成：
return （sqlmapper）ibatisnet.datamapper.mapper.instance （);

发表于：2007-02-05 14:41:063楼得分:0

bestshl（快乐的coder) ,异常感谢，就是那个问题，已通过编译。

发表于：2007-02-05 16:42:554楼得分:0

新问题如下：恕小弟愚笨，谁帮我看看，解决后追加分！
--------------------------------------------------------------------------------
“/webview”应用程序中的服务器错误。
--------------------------------------------------------------------------------

未将对象引用设置到对象的实例。
说明: 执行当前 web 请求期间，出现未处理的异常。请检查堆栈跟踪信息，以了解有关该错误以及代码中导致错误的出处的详细信息。

异常详细信息: system.nullreferenceexception: 未将对象引用设置到对象的实例。

源错误:

行 22: private void list_load （)
行 23: {
行 24: dglist.datasource = helpers.person（).selectall（);
行 25: dglist.databind （);
行 26: }

源文件: d:\zyt_web\donet\tutorial\webview\forms\person.aspx.cs 行: 24

堆栈跟踪:

[nullreferenceexception: 未将对象引用设置到对象的实例。]
ibatisnet.datamapper.configuration.domsqlmapbuilder.parseglobalproperties（) +96
ibatisnet.datamapper.configuration.domsqlmapbuilder.initialize（) +258
ibatisnet.datamapper.configuration.domsqlmapbuilder.build（xmldocument document, datasource datasource, boolean useconfigfilewatcher, boolean iscallfromdao) +234

[configurationexception:
- the error occurred while validate sqlmap config.]
ibatisnet.datamapper.configuration.domsqlmapbuilder.build（xmldocument document, datasource datasource, boolean useconfigfilewatcher, boolean iscallfromdao) +288
ibatisnet.datamapper.configuration.domsqlmapbuilder.configureandwatch（string resource, configurehandler configuredelegate) +209
ibatisnet.datamapper.mapper.initmapper（) +71
ibatisnet.datamapper.mapper.instance（) +62
ibatistutorial.model.helper.mapper（) +6
ibatistutorial.model.personhelper.selectall（) +4
ibatistutorial.web.forms.personpage.list_load（) in d:\zyt_web\donet\tutorial\webview\forms\person.aspx.cs:24
ibatistutorial.web.forms.personpage.page_load（object sender, eventargs e) in d:\zyt_web\donet\tutorial\webview\forms\person.aspx.cs:88
system.web.ui.control.onload（eventargs e) +80
system.web.ui.control.loadrecursive（) +49
system.web.ui.page.processrequestmain（boolean includestagesbeforeasyncpoint, boolean includestagesafterasyncpoint) +3745

--------------------------------------------------------------------------------
版本信息: microsoft .net framework 版本:2.0.50727.42; asp.net 版本:2.0.50727.42
---------------------------------------------------------------------------------

配置文件：

sqlmap.config 位于根目录
---------------------------------------------------------------------------------
<?xml version= "1.0 " encoding= "utf-8 " ?>
<sqlmapconfig xmlns:xsi= "http://www.w3.org/2001/xmlschema-instance " xsi:nonamespaceschemalocation= "sqlmapconfig.xsd ">

  <properties resource= "properties.config "/>
 
<settings>
<setting usestatementnamespaces= "false "/>
<setting cachemodelsenabled= "true "/>
</settings>

<database>
<provider name= "${provider} "/>
<datasource name= "ibatistutorial " connectionstring= "${connectionstring} "/>
</database>

<sqlmaps>
<sqlmap resource= "${root}map/personhelper.xml "/>
</sqlmaps>

</sqlmapconfig>
------------------------------------------------------------------------------------
properties.config 位于根目录
------------------------------------------------------------------------------------
<?xml version= "1.0 " encoding= "utf-8 " ?>
<settings>


<add key= "provider " value= "oledb1.1 " />
<add
key= "connectionstring "
value= "provider=microsoft.jet.oledb.4.0;data source=data/ibatistutorial.mdb " />
<add key= "root " value= "./ " />
</settings>
---------------------------------------------------------------------------------

personhelper.xml 位于根目录下 map文件夹

---------------------------------------------------------------------------------
<?xml version= "1.0 " encoding= "utf-8 " ?>

<sqlmap
namespace= "person "
xmlns:xsi= "http://www.w3.org/2001/xmlschema-instance "
xsi:nonamespaceschemalocation= "sqlmap.xsd ">



<alias>
<typealias alias= "person " type= "ibatistutorial.model.person, ibatistutorial.model " />
</alias>

<resultmaps>
<resultmap id= "selectresult " class= "person ">
<result property= "id " column= "per_id " />
<result property= "firstname " column= "per_first_name " />
<result property= "lastname " column= "per_last_name " />
<result property= "birthdate " column= "per_birth_date " />
<result property= "weightinkilograms " column= "per_weight_kg " />
<result property= "heightinmeters " column= "per_height_m " />
</resultmap>
</resultmaps>

<statements>

<select id= "select " parameterclass= "int " resultmap= "selectresult ">
select
per_id,
per_first_name,
per_last_name,
per_birth_date,
per_weight_kg,
per_height_m
from person
<dynamic prepend= "where ">
<isparameterpresent>
per_id = #value#
</isparameterpresent>
</dynamic>
</select>

<insert id= "insert " parameterclass= "person ">
insert into person
（per_id, per_first_name, per_last_name,
per_birth_date, per_weight_kg, per_height_m)
values
（#id#, #firstname#, #lastname#,
#birthdate#, #weightinkilograms#, #heightinmeters#)
</insert>

<update id= "update " parameterclass= "person ">
update person set
per_first_name = #firstname#,
per_last_name = #lastname#,
per_birth_date = #birthdate#,
per_weight_kg = #weightinkilograms#,
per_height_m = #heightinmeters#
where per_id = #id#
</update>

<delete id= "delete " parameterclass= "int ">
delete from person
where per_id = #value#
</delete>

</statements>

</sqlmap>
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