Sharepoint 2010 Custom Webpart - Access Denied Error

we've created a custom webpart to display announcements from all lists a user has access to, removing a few. The error we are having is that the webpart works fine on the page for the administrators, but when testing with regular user accounts, they are unable to see the page at all and are given a Access Denied error which is coming from the webpart itself.

Only when a user is added as a Site Collection Administrator they can see the page and have access to the webpart. What I'd like some advice on is how to be able to apply full read permissions to a select group within the code itself.

Below is the backend code

using System;
using System.Data;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using Microsoft.SharePoint;

namespace Test.TestWebPart
{

    public partial class TestWebPartUserControl : UserControl
    {
        //Global variable call
        private SPSite thisSite = SPContext.Current.Site;
        private SPWebCollection thisWeb;
        private DataTable dt;
        private SPListCollection siteLists;
        private DataTableWrapper myDataTable;

        //Occurs when the page loads
        protected void Page_Load(object sender, EventArgs e)
        {
            //Pulls all the websites in the site into a webcollection
            thisWeb = thisSite.AllWebs;

            //If the page is not postback call BindToGrid()
            if (!Page.IsPostBack)
            {
                BindToGrid();
            }
        }

        private void BindToGrid()
        {
            //Create a new DataTable along with the columns and headers
            dt = new DataTable();
            dt.Columns.Add("Title");
            dt.Columns.Add("Created");
            dt.Columns.Add("List");

            //Call to populate the DataTable
            dt = SelectData();

            //Populate DataTableWrapper class and get the type
            myDataTable = new DataTableWrapper(dt);
            Type t = myDataTable.GetType();

            //Create a ObjectDataSource to hold data and bind to spgridview
            ObjectDataSource ds = new ObjectDataSource();
            ds.ID = "myDataSource";
            ds.TypeName = t.AssemblyQualifiedName;
            ds.SelectMethod = "GetTable";
            ds.ObjectCreating += new ObjectDataSourceObjectEventHandler(ds_ObjectCreating);
            this.Controls.Add(ds);

            grid.ID = "gridID";

            BoundField column = new BoundField();
            column.DataField = "Title";
            column.HtmlEncode = false;
            //column.SortExpression = "Title";
            column.HeaderText = "Title";
            grid.Columns.Add(column);

            BoundField column1 = new BoundField();
            column1.DataField = "Created";
            column1.HtmlEncode = true;
            //column1.SortExpression = "Created";
            column1.HeaderText = "Created";
            grid.Columns.Add(column1);

            BoundField column2 = new BoundField();
            column2.DataField = "List";
            column2.HtmlEncode = false;
            //column2.SortExpression = "List";
            column2.HeaderText = "List";
            grid.Columns.Add(column2);


            //Provide the SPGridview with the DataSource
            grid.DataSourceID = "myDataSource";
            this.Controls.Add(grid);

            //grid.PageSize =10;
            //grid.AllowPaging = true;

            //Default Pagination - commented out due to not working
            //grid.PageIndexChanging += new GridViewPageEventHandler(grid_PageIndexChanging);
            //grid.PagerTemplate = null;

            //Bind the data to the grid
            grid.DataBind();

        }

        //private void GenerateColumns()
        //{

        //}

        //Used to deal with the PageIndexChange event
        void grid_PageIndexChanging(object sender, GridViewPageEventArgs e)
        {
            grid.PageIndex = e.NewPageIndex;
            grid.DataBind();
        }

        //Used to deal with the ObjectCreated event
        void ds_ObjectCreating(object sender, ObjectDataSourceEventArgs e)
        {
            myDataTable = new DataTableWrapper(dt);
            e.ObjectInstance = myDataTable;
        }

        //Pulls the data from lists which will be displayed
        public DataTable SelectData()
        {
            try
            {
                //Create a new instance of type DataRow
                DataRow row;

                //Loop through each website in the webcollection
                foreach (SPWeb web in thisWeb开发者_JS百科)
                {
                    //Pull the lists from the site into a list collection
                    siteLists = web.Lists;
                    //Display only lists the current user has access to
                    siteLists.ListsForCurrentUser = true;

                    //Loop through each list within the list collection
                    foreach (SPList list in siteLists)
                    {

                            //If the list is an announcement list continue otherwise skip
                            if (list.BaseTemplate.ToString() == "Announcements")
                            {
                                //Exclude the lists stated from those whose data will be collected
                                if (list.Title.ToString() == "Bulletins" || list.Title.ToString() == "The Buzz - Curriculum" || list.Title.ToString() == "The Buzz - Personal" || list.Title.ToString() == "The Buzz - Support" || list.Title.ToString() == "Critical Annoucements")
                                {
                                }
                                else
                                {
                                    //Create a item collection for each item within the current list
                                    SPListItemCollection listItem = list.Items;

                                    //Loop through each item within the item collection
                                    foreach (SPListItem item in listItem)
                                    {
                                        //Get the url of the current website
                                        string weburl = web.Url;
                                        //Gets the URL of the current item
                                        string dispurl = item.ContentType.DisplayFormUrl;
                                        dispurl = list.Forms[PAGETYPE.PAGE_DISPLAYFORM].Url;

                                        //Joins together the full URL for the current item into a single variable
                                        dispurl = string.Format("{0}/{1}?ID={2}", weburl, dispurl, item.ID);
                                        //Create a new in the datatable as an instance of row
                                        row = dt.Rows.Add();

                                        //Put the correct information and links into the correct column
                                        row["Title"] = "<a target=_blank href=\"" + dispurl + "\">" + item["Title"].ToString() + "</a>";
                                        row["Created"] = item["Created"].ToString();
                                        row["List"] = "<a target=_blank href=\"" + list.DefaultViewUrl + "\">" + list.Title + "</a>";
                                    }
                                }
                            }
                    }
                }
                //Return the completed DataTable
                return dt;
            }

            //Exception to catch any errors
            catch (Exception s)
            {
                return dt;
            }
        }
    }
}

Thanks

thisWeb = thisSite.AllWebs;

This code requires Administrator previliges. Run it under Elevated Previleges: http://msdn.microsoft.com/en-us/library/microsoft.sharepoint.spsecurity.runwithelevatedprivileges.aspx

Based on the above comments and edited changes, here is the full working code, encase anyone was wondering:-

using System;
using System.Data;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using Microsoft.SharePoint;

namespace Test.TestWebPart
{
    public partial class TestWebPartUserControl : UserControl
    {
        //Global variable call
        private SPSite thisSite = SPContext.Current.Site;
        //private SPWebCollection thisWeb;//
        private SPWeb thisWeb = SPContext.Current.Web;
        private DataTable dt;
        private SPListCollection siteLists;
        private DataTableWrapper myDataTable;


        //Occurs when the page loads
        protected void Page_Load(object sender, EventArgs e)
        {
            //Pulls all the websites in the site into a webcollection
            //thisWeb = thisSite.AllWebs.;//

            //If the page is not postback call BindToGrid()
            if (!Page.IsPostBack)
            {
                BindToGrid();
            }
        }

        private void BindToGrid()
        {
            //Create a new DataTable along with the columns and headers
            dt = new DataTable();
            dt.Columns.Add("Title");
            dt.Columns.Add("Created");
            dt.Columns.Add("List");

            //Call to populate the DataTable
            dt = SelectData();

            //Populate DataTableWrapper class and get the type
            myDataTable = new DataTableWrapper(dt);
            Type t = myDataTable.GetType();

            //Create a ObjectDataSource to hold data and bind to spgridview
            ObjectDataSource ds = new ObjectDataSource();
            ds.ID = "myDataSource";
            ds.TypeName = t.AssemblyQualifiedName;
            ds.SelectMethod = "GetTable";
            ds.ObjectCreating += new ObjectDataSourceObjectEventHandler(ds_ObjectCreating);
            this.Controls.Add(ds);

            grid.ID = "gridID";


            //Sorting, Filtering & paging does not work so has been commented out for now
            //this.grid.AllowSorting = true;


            //Bind the three columns to the SPGridView
            //HtmlEncode must be false for the links to appear as true html
            BoundField column = new BoundField();
            column.DataField = "Title";
            column.HtmlEncode = false;
            //column.SortExpression = "Title";
            column.HeaderText = "Title";
            grid.Columns.Add(column);

            BoundField column1 = new BoundField();
            column1.DataField = "Created";
            column1.HtmlEncode = true;
            //column1.SortExpression = "Created";
            column1.HeaderText = "Created";
            grid.Columns.Add(column1);

            BoundField column2 = new BoundField();
            column2.DataField = "List";
            column2.HtmlEncode = false;
            //column2.SortExpression = "List";
            column2.HeaderText = "List";
            grid.Columns.Add(column2);


            //Has been commented out due to these sections not working
            //grid.AllowFiltering = true;

            //grid.FilterDataFields = "Title";
            //grid.FilteredDataSourcePropertyName = "FilterExpression";
            //grid.FilteredDataSourcePropertyFormat = "{1} like '{0}'";

            //grid.FilterDataFields = "Created";
            //grid.FilteredDataSourcePropertyName = "FilterExpression";
            //grid.FilteredDataSourcePropertyFormat = "{1} like '{0}'";

            //grid.FilterDataFields = "ListName";
            //grid.FilteredDataSourcePropertyName = "FilterExpression";
            //grid.FilteredDataSourcePropertyFormat = "{1} like '{0}'";

            //Provide the SPGridview with the DataSource
            grid.DataSourceID = "myDataSource";
            this.Controls.Add(grid);

            //grid.PageSize =10;
            //grid.AllowPaging = true;

            //Default Pagination - commented out due to not working
            //grid.PageIndexChanging += new GridViewPageEventHandler(grid_PageIndexChanging);
            //grid.PagerTemplate = null;

            //Bind the data to the grid
            grid.DataBind();

        }

        //private void GenerateColumns()
        //{

        //}

        //Used to deal with the PageIndexChange event
        void grid_PageIndexChanging(object sender, GridViewPageEventArgs e)
        {
            grid.PageIndex = e.NewPageIndex;
            grid.DataBind();
        }

        //Used to deal with the ObjectCreated event
        void ds_ObjectCreating(object sender, ObjectDataSourceEventArgs e)
        {
            myDataTable = new DataTableWrapper(dt);
            e.ObjectInstance = myDataTable;
        }

        //Pulls the data from lists which will be displayed
        public DataTable SelectData()
        {
            try
            {
                //Create a new instance of type DataRow
                DataRow row;

                //Loop through each website in the webcollection

                {
                    //Pull the lists from the site into a list collection
                    siteLists = thisWeb.Lists;
                    //Display only lists the current user has access to
                    siteLists.ListsForCurrentUser = true;

                    SPBasePermissions perms = SPBasePermissions.ViewListItems;

                    //Loop through each list within the list collection
                    foreach (SPList list in siteLists)
                    {
                        if (list.DoesUserHavePermissions(perms))
                        {
                            //If the list is an announcement list continue otherwise skip
                            if (list.BaseTemplate.ToString() == "Announcements")
                            {
                                //Exclude the lists stated from those whose data will be collected
                                if (list.Title.ToString() == "The Buzz" || list.Title.ToString() == "Test 2 list")
                                {
                                }
                                else
                                {
                                    //Create a item collection for each item within the current list
                                    SPListItemCollection listItem = list.Items;

                                    //Loop through each item within the item collection
                                    foreach (SPListItem item in listItem)
                                    {
                                        //Get the url of the current website
                                        string weburl = thisWeb.Url;
                                        //Gets the URL of the current item
                                        string dispurl = item.ContentType.DisplayFormUrl;
                                        dispurl = list.Forms[PAGETYPE.PAGE_DISPLAYFORM].Url;

                                        //Joins together the full URL for the current item into a single variable
                                        dispurl = string.Format("{0}/{1}?ID={2}", weburl, dispurl, item.ID);
                                        //Create a new in the datatable as an instance of row
                                        row = dt.Rows.Add();

                                        //Put the correct information and links into the correct column
                                        row["Title"] = "<a target=_blank href=\"" + dispurl + "\">" + item["Title"].ToString() + "</a>";
                                        row["Created"] = item["Created"].ToString();
                                        row["List"] = "<a target=_blank href=\"" + list.DefaultViewUrl + "\">" + list.Title + "</a>";
                                    }
                                }
                            }
                        }
                    }
                }
                //Return the completed DataTable
                return dt;
            }

            //Exception to catch any errors
            catch (Exception s)
            {
                return dt;
            }
        }
    }
}

SPWeb.GetSubwebsForCurrentUser() should be used. It gets SubWebs that current user has access to. Avoid using ElevatedPriveleges until you absolutely need it.