Solve | problem | project
1. A potentially dangerous Request.Form value was detected
Reason:
(1) The ValidateRequest property is not properly set on the page or webconfig on which the data is submitted
(2) The HTML inside wrote two causes
Solve:
Scenario One: Add this sentence to the header of the. aspx file: <%@ Page validaterequest= "false"%>
Programme II: Modification of the Web.config file:
<configuration>
<system.web>
<pages validaterequest= "false"/>
</system.web>
</configuration>
Because the default value of ValidateRequest is true. Just set to false.
2. "Invalid read attempt in the absence of any data" solution
Reason:
The returned SqlDataReader have no data records, but are not treated as a record of judgment. Returns a null value
Plus judgment: if (Reader.read ()) {Textname.text =
reader["FieldName"]. ToString (); }
3. The data is empty. This method or property cannot be called on null values.
Reason:
If the object is null, then the method of invoking the object, such as ToString () is definitely an error, usually the value of the database field is null
Data controls such as Grideview often appear
WORKAROUND: Therefore, null processing is recommended
4. The FieldCount attempt is invalid when the reader closes
Reason:
After using the SqlDataReader to bind the data, the connection object is treated as close ()
Similar
Public SqlDataReader getsomething ()
{
Conn.Open ();
SqlDataReader reader =
sqlcmd. Excecutreader (commandbehavior.closeconnection));
Conn.close ()///occur error here
return reader;
}
This method is called when binding to specify the data source. If you use this method, you need to close the re in the calling function
Ader So conn can be closed automatically.
If you are using SqlDataAdapter and datasets, remove the call that explicitly closes the Conn. or in finally
Called in.
5. Failed to map path
Cause: May be caused by incorrect path configuration in Webconfig
<add key= "Fckeditor:basepath" value= "~/admin/fckeditor/"/>
<add key= "Fckeditor:userfilespath" value= "/userfiles/"/>
6.Unreachable Code Detected
Reason:
Typically, the throw or return is used when the exception is handled or returned, possibly in front of it, causing the following code to execute.
Solve:
Put the associated exception-throwing statement (throw) or return statement on the last line of the agent execution.
7. Index out of range. Must be non-negative and less than the collection size
Reason:
(1). DataKeyField set as the corresponding unique field in the database (typically primary key)
(2). Datagrid1.columns > E.item.cells
Solve:
(1). Set DataKeyField
(2). Add Judgment Statement Datagrid1.item.count (DataGrid can be other similar server controls)
8. The data is empty. This method or property cannot be called on null values
9. Data source does not support server-side paging of data
Workaround:
Do not use DataReader, change to use dataset: or use custom paging, do not use the paging functionality provided by vs.net
OleDbDataAdapter da = new OleDbDataAdapter (sql, connection);
DataSet ds2 = new DataSet ();
Da. Fill (DS2, "News");
Gridview1.datasource = DS2;
Gridview1.databind ();
10. The object name ' * * * * is invalid
Reason: This table is not present in the database currently in use
Workaround: See if the program has written the name of the table you called or whether the table you called is present in the SQL database
11. An error occurred while establishing a connection to the server. When connecting to SQL Server 2005, the default settings for SQL
This failure may be caused by the Server not allowing remote connections. (provider: Named pipe provider,
ERROR:40-Unable to open connection to SQL Server
Solution: A fixed IP address or server address is required on the host
12.SqlDateTime overflow. Must be between 1/1/1753 12:00:00 AM and 12/31/9999 11:59:59 PM
Between.
This problem occurs ' mostly because you update the database ' DateTime field value is empty ' by default insert January 01 01
Day ' ' causes datetime type Overflow
13. The appearance of the-------represents "properties", where the "method" should be
Reason:
1.VB method with C #, the format of the property is different.
2. It is possible that the syntax for binding data in design is incorrectly resolved: 1. Remember that attributes are used with the [] method ()
3. Remember the correct syntax for binding data (in several ways:: <%container.dataitem ("field name")%> <%
#Eval ("field name")%><%bind ("field name")%>, etc.)
14. Failed from the Assembly "DAL, version=1.0.0.0, Culture=neutral,
Publickeytoken=null the "load type" DAL. SqlHelper ".
Reason: Failed to recompile to DLL after other layers have been modified
Resolution: Compile (Rebuild)
15. Too many parameters specified for a procedure or function
Solution: The number of parameters used to invoke stored procedures with defined stored procedures or the incoming arguments in the executed SQL statement
Inconsistent number of numbers (this is a SQL error)
Solution: Carefully examine the parameter variables that are set in the stored procedure and correspond to the actual input parameter values of one by one
16. Unable to start debugging, invalid binding handle
Cause: The system's Terminal Services are not open
17.Unable to debugging on the Web server. Debug failed because Integrated Windows authentication is not enable
Workaround:
Open the Vs2005-> tool (Tools)-> option-> Debugging (Debugging)-> Edit and Continue (Edit and Continue)-> all tick
File name or class name not found in 18.Automation operation: ' RegExp '
Workaround: regsvr32 vbscript.dll
19.system.nullreferenceexception: Object references are not set to an instance of an object.
Reason:
(1) The variable being set is NULL or does not have a value, typically occurs when passing parameters, and also occurs when using data controls such as the DataGrid or GridView or DataList.
(2) The control name does not correspond to the codebehind inside
(3) Initialization of object not with new
(4) The control referenced in the program does not exist
Workaround:
(1) Use Try ... Catch...finally catch the error, or output the variable value directly with Response.Write ()
(2) To see if there are any uninitialized variables in the code
20. Error 1718. File is rejected by digital signature policy (when VS2005SP1 is installed)
Workaround:
(1). Click Start, click Run, type Control AdminTools, and then click OK.
(2). Double-click Local Security Policy.
(3). Click Software Restriction Policy. (Note: If the software restrictions are not listed, right-click Software restriction Policies, and then click New Policy.) )
(4). Under Object type, double-click coercion.
(5). Click All users except local administrators, and then click OK.
(6). Restart the computer.
Microsoft notes:
http://support.microsoft.com/kb/925336
21.vs2005 cannot switch from source file mode to view mode
Solution: Under DOS run under devenv/resetskippkgs (win+r cmd)
22.Validation of ViewState MAC failed
Workaround: Page with enableviewstate= "false" enableViewStateMac = "false" to solve the problem
23.Automation server can ' t create object ' (Automation server cannot be created right)
Solution: Run: Regsvr32 Scrrun.dll can be.
24. Package Load failed
The package "Visual Web Developer Trident Designer Package" was not loaded correctly (GUID =
{30ae7e28-6c02-496d-8e43-85f7a90aeff1}.
Workaround:
1. Set the system variable Vslogactivity=1
2, create the file under the%appdata%\microsoft\visualstudio\8.0\ folder Activitylog.xml
Error
Microsoft Visual Studio
LoadLibrary failed for package [Visual Web Developer Trident Designer Package]
{30AE7E2B-6C02-496D-8E43-85F7A90AEFF1}
-------------------------------------------------
8007007e
C:\Program Files\Microsoft Visual Studio 8\common7\packages\tridsn.dll
3. Copy files from winnt\microsoft.net\framework\v2.0.xxx gdiplus.dll to program files\visual Studio 8\common7\packages folder
4. Run the command at the command line: devenv/resetskippkgs
25.Error spawning ' cmd.exe '.
Solution: Copy the Cmd.exe to the Vc/bin directory under the VS installation directory to solve the problem.
26. Attempt to read or write protected memory
Resolution: Hardware problems, general memory problems
27. Unable to find the manifest signing certificate in the certificate store
WORKAROUND: Open the project's. csproj file with Notepad and delete the similar
28. There is no target "ResolveKeySource" in the project.
Reason: This question is very rare, inquires the overseas related material, basically is because deploys is not a standard solution, needs to run the following this thing to restore in the VS from the command prompt
Workaround:
(1). Save the following code as an XML file named Testbuild.xml
<project defaulttargets= "Build" xmlns= "http://schemas.microsoft.com/developer/msbuild/2003" >
<PropertyGroup>
<targetconnectionstring>data Source=.\sql2005%3buser id=sqluser%3bpooling=false%3bpassword=x</ Targetconnectionstring>
</PropertyGroup>
<ItemGroup>
<databaseproject include= "Database1\database1.dbproj"/>
<databaseproject include= "Database2\database2.dbproj"/>
</ItemGroup>
<target name= "Buildalldatabaseprojects" >
<msbuild
Properties= "targetconnectionstring=$ (targetconnectionstring)"
Projects= "@ (DatabaseProject)"
targets= "Build;deploy" >
</MSBuild>
</Target>
(2) run in command prompt: Msbuild/t:buildalldatabaseprojects testbuild.xml
29. Cannot insert value NULL into column ' * * '
Reason: This is a database table design error, the table involved in the field has set the NOT NULL attribute, but the passed value is null, so the error
Workaround: See if the value passed in is null, or modify the properties of the column corresponding to the table in the database
30. Failed to load type "namespace. Class" ...
Reason:
(1) The project has not been compiled after the modification
(2) Some of the namespaces in the project may have been modified
(3) The required ascx or other pages in the project do not exist or are not included in the project
Workaround:
(1) Rebuild or compile the entire project or solution after the modification is complete
(2) Manually modify the namespace changed, pay attention to the case of the name, and then recompile
(3) Include related files in the project
31. Cannot access read-only file "****.***"
Solution:
Add "everyone/write" permission to the file corresponding to the virtual directory
32. Request failed for HTTP status 401: Access Denied
Workaround: Anonymous access on the IIS Information Server and allow IIS to control the password on the hook