سلام دوستان میتونید راهنمایی کنید این خطا بخاطر چیه

Server Error in '/' Application.

A field or property with the name 'userid' was not found on the selected data source.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.Web.HttpException: A field or property with the name 'userid' was not found on the selected data source.

Source Error: 

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace: 


[HttpException (0x80004005): A field or property with the name 'userid' was not found on the selected data source.]
   System.Web.UI.WebControls.BoundField.TryGetSimplePropertyValue(Object dataItem, Object& data) +3243867
   System.Web.UI.WebControls.BoundField.GetValue(Control controlContainer) +209
   System.Web.UI.WebControls.BoundField.OnDataBindField(Object sender, EventArgs e) +58
   System.Web.UI.Control.OnDataBinding(EventArgs e) +92
   System.Web.UI.Control.DataBind(Boolean raiseOnDataBinding) +85
   System.Web.UI.Control.DataBind() +15
   System.Web.UI.Control.DataBindChildren() +187
   System.Web.UI.Control.DataBind(Boolean raiseOnDataBinding) +94
   System.Web.UI.Control.DataBind() +15
   System.Web.UI.WebControls.GridView.CreateRow(Int32 rowIndex, Int32 dataSourceIndex, DataControlRowType rowType, DataControlRowState rowState, Boolean dataBind, Object dataItem, DataControlField[] fields, TableRowCollection rows, PagedDataSource pagedDataSource) +167
   System.Web.UI.WebControls.GridView.CreateChildControls(IEnumerable dataSource, Boolean dataBinding) +3724
   System.Web.UI.WebControls.CompositeDataBoundControl.PerformDataBinding(IEnumerable data) +67
   System.Web.UI.WebControls.GridView.PerformDataBinding(IEnumerable data) +14
   System.Web.UI.WebControls.DataBoundControl.OnDataSourceViewSelectCallback(IEnumerable data) +123
   System.Web.UI.DataSourceView.Select(DataSourceSelectArguments arguments, DataSourceViewSelectCallback callback) +33
   System.Web.UI.WebControls.DataBoundControl.PerformSelect() +138
   System.Web.UI.WebControls.BaseDataBoundControl.DataBind() +30
   System.Web.UI.WebControls.GridView.DataBind() +4
   System.Web.UI.WebControls.BaseDataBoundControl.EnsureDataBound() +105
   System.Web.UI.WebControls.CompositeDataBoundControl.CreateChildControls() +75
   System.Web.UI.Control.EnsureChildControls() +83
   System.Web.UI.Control.PreRenderRecursiveInternal() +42
   System.Web.UI.Control.PreRenderRecursiveInternal() +155
   System.Web.UI.Control.PreRenderRecursiveInternal() +155
   System.Web.UI.Control.PreRenderRecursiveInternal() +155
   System.Web.UI.Control.PreRenderRecursiveInternal() +155
   System.Web.UI.Control.PreRenderRecursiveInternal() +155
   System.Web.UI.Control.PreRenderRecursiveInternal() +155
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +974

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.34248