SPWorkflow AlterTask didn’t work with hash table which has space into key name

While creating hash table for passing into altertask method, we need to be very careful, because it didn’t like spaces into key name, we need to put our key without spaces.

Sample Code:

taskHash["UserInputField"] = UserInputField.Text;

taskHash["UserInputField_ForHash"] = UserInputField.Text;

taskHash["Status"] = "Completed";

taskHash["Status_ForHash"] = "Completed";

SPWorkflowTask.AlterTask(taskListItem, taskHash, true);

Reference Link:

http://www.databaseforum.info/10/1131769.aspx

ERROR: The security validation for this page is invalid. Click Back in your Web browser, refresh the page, and try your operation again

I was getting above error while doing altertask on SPWorkflowTask.AlterTask method.

Solution:  we need to write altertask code under SPSecurity delegate and need to write code for Allowunsafeaccess.

http://sansanwal.blogspot.com/2009/08/security-validation-for-this-page-is.html

http://support.microsoft.com/default.aspx?scid=kb;EN-US;970192