不了解错误消息（数据库） [英] Don't Understand Error Message (Database)
问题描述
以下代码引发错误指定的转换无效。
MembershipUser user = Membership.GetUser（userId）;
DataSet ds = DataLayer.ExecQueryData（" SELECT * FROM mc_Clients WHERE
UserId =''" + userId.ToString（）+"''"）;
if（ds == null || ds.Tables.Count == 0 || ds.Tables [0] .Rows.Count == 0）
返回null;
ClientEx client = new ClientEx（）;
client.ClientData = new Client（）;
client.ClientData.Email = user.UserName;
client.ClientData.UserID = user.ProviderUserKey;
client.ClientData.LastLogin = user.LastLoginDate;
DataRow dr = ds.Tables [0] .Rows [ 0];
// ...
if（！Convert.IsDBNull（dr [" Sex"]））
client.Sex =（int）dr [" Sex"]; < ==错误在这里！
// ...
在数据库表中，Sex的数据类型= smallint和nullable = True，并且
client.Sex的数据类型为int。
如果我试图检查dr [" Sex" ]在调试器中，它显示
a值为0x0000。如果我试图在调试器中检查
中的（int）dr [" Sex"]的内容，它会显示一个关于无法取消装箱的错误（抱歉，我没有
更长的确切文字）。
有什么建议吗？
-
乔纳森伍德
SoftCircuits编程
http://www.softcircuits.com
" Jonathan Wood" < jw *** @ softcircuits.com写信息
新闻：％2 ****************** @ TK2MSFTNGP04.phx.gbl .. 。
以下代码引发错误指定的强制转换无效。
是的，它会......
if（！Convert.IsDBNull（dr [" ;性别"]））
if（dr [" Sex"]！= DBNull.Value）
在数据库表中，Sex的数据类型= smallint
因此，Sex字段的值范围可以从-32,768到32,767 ...？
http：// msdn2 .microsoft.com / zh-CN / lib ... 8（SQL.80）.aspx
-
Mark Rae
ASP.NET MVP
http://www.markrae.net
client.Sex是什么类型的？看起来不管它是什么，它都不能接受int作为
值。除非（int）dr [" Sex]的转换失败，因为它
本身不是整数。
- Peter
网站： http://www.eggheadcafe.com
UnBlog： http://petesbloggerama.blogspot.com
MetaFinder： http://www.blogmetafinder.com
Jonathan Wood写道：
以下代码引发错误指定的演员表无效。
MembershipUser user = Membership .GetUser（userId）;
DataSet ds = DataLayer.ExecQueryData（" SELECT * FROM mc_Clients WHERE
UserId =''" + userId.ToString（）+" ;''"）;
if（ds == null || ds.Tables.Count == 0 || ds.Tables [0] .Rows.Count == 0）
返回null;
ClientEx client = new ClientEx（）;
client.ClientData = new Client（）;
client .ClientData.Email = user.UserName;
client.ClientData.UserID = user.ProviderUserKey;
client.ClientData.LastLogin = user.LastLoginDate;
DataRow dr = ds.Tables [0] .Rows [0];
// ...
if（！ Convert.IsDBNull（dr [" Sex"]））
client.Sex =（int）dr [" Sex"]; < ==错误在这里！
// ...
在数据库表中，Sex的数据类型= smallint和nullable = True，并且
client.Sex的数据类型为int。
如果我试图检查dr [" Sex" ]在调试器中，它显示
a值为0x0000。如果我试图在调试器中检查
中的（int）dr [" Sex"]的内容，它会显示一个关于无法取消装箱的错误（抱歉，我没有
更长的确切文字）。
有什么建议吗？
-
乔纳森伍德
SoftCircuits编程
http://www.softcircuits.com
如上所述，client.Sex是一个int。
-
Jonathan Wood
SoftCircuits编程
http： //www.softcircuits.com
" Peter Bromberg [C＃MVP]" < pb ******* @ yahoo.NoSpamMaam.com写信息
news：23 ********************* ************* @ microsof t.com ...
什么类型的client.Sex？看起来不管它是什么，它都不能接受$
作为
值。除非（int）dr [" Sex]的转换失败，因为它
本身不是整数。
- Peter
网站： http://www.eggheadcafe.com
UnBlog： http://petesbloggerama.blogspot.com
MetaFinder： http://www.blogmetafinder.com
Jonathan Wood写道：
>以下代码引发错误指定的演员表无效。
MembershipUser user = Membership.GetUser （userId）;
DataSet ds = DataLayer.ExecQueryData（" SELECT * FROM mc_Clients WHERE
UserId =''" + userId.ToString（）+"''"）;
if（ds == null || ds.Tables.Count == 0 || ds.Tables [0] .Rows.Count ==
0）
返回null;
ClientEx客户端= new ClientEx（）;
client.ClientData = new Client（）;
client.ClientData.Email = user.UserName;
client.ClientData.UserID = user.ProviderUserKey;
client.ClientData.LastLogin = user.LastLoginDate;
DataRow dr = ds.Tables [0] .Rows [0];
// ...
if（！Convert.IsDBNull（dr [" Sex"]））
client.Sex =（int）dr [" Sex"]; < ==错误在这里！
// ...
在数据库表中，Sex的数据类型为= smallint，nullable = True，和
client.Sex的数据类型为int。
如果我试图在调试器中检查dr [" Sex"]的内容，它会显示
值为0x0000。如果我试图在调试器中检查（int）dr [" Sex"]
的内容，它会显示一个关于无法取消包装的错误（抱歉，我没有
更长的时间）确切的文字。
有什么建议吗？
-
Jonathan Wood
SoftCircuits编程
http://www.softcircuits.com
The following code raises the error "Specified cast is not valid."
MembershipUser user = Membership.GetUser(userId);
DataSet ds = DataLayer.ExecQueryData("SELECT * FROM mc_Clients WHERE
UserId=''" + userId.ToString() + "''");
if (ds == null || ds.Tables.Count == 0 || ds.Tables[0].Rows.Count == 0)
return null;
ClientEx client = new ClientEx();
client.ClientData = new Client();
client.ClientData.Email = user.UserName;
client.ClientData.UserID = user.ProviderUserKey;
client.ClientData.LastLogin = user.LastLoginDate;
DataRow dr = ds.Tables[0].Rows[0];
// ...
if (!Convert.IsDBNull(dr["Sex"]))
client.Sex = (int)dr["Sex"]; <<== ERROR HERE!
// ...
In the database table, Sex has a data type=smallint and nullable=True, and
client.Sex has a data type of int.
If I attempt to examine the contents of dr["Sex"] in the debugger, it shows
a value of 0x0000. If I attempt to examine the contents of (int)dr["Sex"] in
the debugger, it shows an error about not being able to unbox (sorry I no
longer have the exact text).
Any suggestions?
--
Jonathan Wood
SoftCircuits Programming
http://www.softcircuits.com
"Jonathan Wood" <jw***@softcircuits.comwrote in message
news:%2******************@TK2MSFTNGP04.phx.gbl...
The following code raises the error "Specified cast is not valid."Yes, it would do...
if (!Convert.IsDBNull(dr["Sex"]))if (dr["Sex"] != DBNull.Value)
In the database table, Sex has a data type=smallintSo the Sex field can have a range of values from -32,768 to 32,767...?
http://msdn2.microsoft.com/en-us/lib...8(SQL.80).aspx
--
Mark Rae
ASP.NET MVP
http://www.markrae.net
What type is client.Sex? Looks like whatever it is, it cannot accept int as a
value. Unless the Convert of the (int)dr["Sex"] is failing because it
itself is not an integer.
-- Peter
Site: http://www.eggheadcafe.com
UnBlog: http://petesbloggerama.blogspot.com
MetaFinder: http://www.blogmetafinder.com
"Jonathan Wood" wrote:
The following code raises the error "Specified cast is not valid."
MembershipUser user = Membership.GetUser(userId);
DataSet ds = DataLayer.ExecQueryData("SELECT * FROM mc_Clients WHERE
UserId=''" + userId.ToString() + "''");
if (ds == null || ds.Tables.Count == 0 || ds.Tables[0].Rows.Count == 0)
return null;
ClientEx client = new ClientEx();
client.ClientData = new Client();
client.ClientData.Email = user.UserName;
client.ClientData.UserID = user.ProviderUserKey;
client.ClientData.LastLogin = user.LastLoginDate;
DataRow dr = ds.Tables[0].Rows[0];
// ...
if (!Convert.IsDBNull(dr["Sex"]))
client.Sex = (int)dr["Sex"]; <<== ERROR HERE!
// ...
In the database table, Sex has a data type=smallint and nullable=True, and
client.Sex has a data type of int.
If I attempt to examine the contents of dr["Sex"] in the debugger, it shows
a value of 0x0000. If I attempt to examine the contents of (int)dr["Sex"] in
the debugger, it shows an error about not being able to unbox (sorry I no
longer have the exact text).
Any suggestions?
--
Jonathan Wood
SoftCircuits Programming
http://www.softcircuits.com
As stated, client.Sex is an int.
--
Jonathan Wood
SoftCircuits Programming
http://www.softcircuits.com
"Peter Bromberg [C# MVP]" <pb*******@yahoo.NoSpamMaam.comwrote in message
news:23**********************************@microsof t.com...What type is client.Sex? Looks like whatever it is, it cannot accept int
as a
value. Unless the Convert of the (int)dr["Sex"] is failing because it
itself is not an integer.
-- Peter
Site: http://www.eggheadcafe.com
UnBlog: http://petesbloggerama.blogspot.com
MetaFinder: http://www.blogmetafinder.com
"Jonathan Wood" wrote:
>The following code raises the error "Specified cast is not valid."
MembershipUser user = Membership.GetUser(userId);
DataSet ds = DataLayer.ExecQueryData("SELECT * FROM mc_Clients WHERE
UserId=''" + userId.ToString() + "''");
if (ds == null || ds.Tables.Count == 0 || ds.Tables[0].Rows.Count ==
0)
return null;
ClientEx client = new ClientEx();
client.ClientData = new Client();
client.ClientData.Email = user.UserName;
client.ClientData.UserID = user.ProviderUserKey;
client.ClientData.LastLogin = user.LastLoginDate;
DataRow dr = ds.Tables[0].Rows[0];
// ...
if (!Convert.IsDBNull(dr["Sex"]))
client.Sex = (int)dr["Sex"]; <<== ERROR HERE!
// ...
In the database table, Sex has a data type=smallint and nullable=True,
and
client.Sex has a data type of int.
If I attempt to examine the contents of dr["Sex"] in the debugger, it
shows
a value of 0x0000. If I attempt to examine the contents of (int)dr["Sex"]
in
the debugger, it shows an error about not being able to unbox (sorry I no
longer have the exact text).
Any suggestions?
--
Jonathan Wood
SoftCircuits Programming
http://www.softcircuits.com
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