Microsoft.SharePoint namespace is not recognized even the DLL has been referenced

Developing a console app using sharepoint 2010 object model in visual studio 2010. Encountered issue where Microsoft.SharePoint namespace is not recognized even project has referenced the SharePoint dll. Solution: Go to project setting and Make sure to target 3.5 .net framework.

There is no control to be placed to the toolbox.erroe loading dll to toolbox.

You created a control dll but it won't load to the toolbox.try one of below to fix it:
1.make there is at least one public class in the name space.
2.make sure the control class has a public constructor that don't require any parameters.

Error:System.Web.HttpException: Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that configuration specifies the same validationKey and validation algorithm.

Error:System.Web.HttpException: Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that <machineKey> configuration specifies the same validationKey and validation algorithm.

Cause:

Solution:Add this to page enableViewStateMac="false"

This option will work perfectly, but it is always advisable to go with specifying the custom key for encryption and decryption in web.config. 


http://forums.asp.net/t/1355367.aspx/1

Object reference not set to an instance of an object when trying to check out document from library WSS30

Object reference not set to an instance of an object when trying to check out document from library WSS30

Resolution:

–>Open you Central Administration site and go to “operations”
–>look for “Alternate Access Mappings”
–>In the page you will find “Alternate Access Mapping Collection” and it will say “Show All”
–>Click on the small arrow point downwards on this “Show All” location and you will get “Change Alternate Access Mapping Collection”
–>Go ahead and choose the Web Application which is responsible for the problem site
–>You will see that there is a URL already showing in “Default” zone
–>You need to specify the URL which is giving you problem in the “Intranet” zone. So it will see like this:
Default: http://matrix
Intranet: http://yagyashree.org
–>Performed IISRESET
–>Now everything should be working fine, you should be able to check-out and edit the office documents

Workflow issue: Multiple instances seem to be running even though they don't show in History List

Workflow: Multiple instances seem to be running even though they don't show in History List.

I have a SPD2007 workflow which will modify a field based on the "Modified By" field. This workflow is set on run on "Modified" or "Changed" events. I only need to get the initial Modify By person. And the workflow need to wait for other users to change another field, which seems to trigger the "Modify By" to be changed. It seems this would reset my initial value again which was based on the initial "Modified By".  So the value changes multiple times during the workflow. The history list didn't show multiple instances running or duplicate actions occurring.

Eventually I took care of the issue by putting a "Pause for 1 minute" behind each of the "Update Item" action.

It seem the workflow triggering run too fast before they could put a stop to it. Because the workflow ends immediately and the "Change" even still fires to some effect which trigger another workflow?

Giving some "Pause" time seems to stop the workfow from trasitioning into another state. Just my guess.

SharePoint Designer: Datasource List/Library window greyed out.

 A user has Full control of the site but when opening the site in SPD the datasource window is greyed out.  The access right to granted individually. It seems adding the user to Owners group takes care of the problem. So somehow somewhere the permission is not propagating correctly.

Steps to check and verify:
 

1.       Open the problem site in SPD

2.       In the Folder List navigate to _catalogs/fpdatasources

3.       Right-click fpdatasources and click the Security tab

4.       Click "Manage permissions using the browser."

5.       Add the appropriate permissions.

Asp.net GridView delete confirmation

    How to ask for confirmation when using the delete command in gridview? By default it just deletes the item right away.

Answer: Disable the "Show Delete" Option and Put below code in the grid template.          

 "
       <asp:TemplateField><ItemTemplate>
                         <asp:LinkButton ID="lnkDeleteBtn" Runat="server" OnClientClick="return ConfirmDelete();"
                                CommandName="Delete">Delete</asp:LinkButton>
                            </ItemTemplate>
        </asp:TemplateField>

"
Also put this piece of javascript in the header section.
"<script type="text/javascript">
    function ConfirmDelete() {
        return confirm("Are you sure to delete?");
    }
</script>"