Access Denied – SharePoint code execution

August 23, 2012 / Kannan / 0 Comments

When doing certain code operations in SharePoint like getting list of templates will lead to “Access Denied” exceptions. For such instances we can wrap the code within the following lines to execute code with elevated privileges.

SPSecurity.RunWithElevatedPrivileges(delegate()
{
        //Code goes here
});

Unable to evaluate expression because the code is optimized or a native frame is on top of the call stack.

August 23, 2012 / Kannan / 0 Comments

We were developing a Server Object Model based functionality in SharePoint involving site creation using template. During development we use to get the following error in quick watch window.

Unable to evaluate expression because the code is optimized or a native frame is on top of the call stack.

To solve this issue we added the following code before the actual statement and issue was solved.

SPSecurity.CatchAccessDeniedException = false;

Deleting a file from library using SharePoint ASMX web service

August 13, 2012 / Kannan / 2 Comments

The following is the code for deleting a particular file from a library using SharePoint ASMX web service.
The technique involves identifying the document ID using “GetListItems” of the file and then executing “UpdateListItems”

public string DeleteFileFromSharePoint(string siteUrl, string libraryName, string fileName, FileDeleteInput input)
    {
        Lists listService = new Lists(); //Web reference of http://<server>/sites/<site>/_vti_bin/lists.asmx
        listService.Url = "http://<server>/sites/<site>/_vti_bin/lists.asmx";
        listService.UseDefaultCredentials = true;
        string sourceUrl = fileName;
        string output = string.Empty;

        try
        {
            int fileId = GetFileIdFromList(siteUrl, libraryName, fileName, listService.Url);

            XmlDocument doc = new XmlDocument();
            XmlElement Batch = doc.CreateElement("Batch");
            Batch.SetAttribute("OnError", "Continue");
            Batch.SetAttribute("ListVersion", "1");
            Batch.SetAttribute("ViewName", "");
            string strBatch = "<Method ID='1' Cmd='Delete'>";
            strBatch += "<Field Name='ID'>" + fileId + "</Field>";
            strBatch += "<Field Name='FileRef'>" + siteUrl + libraryName + "/" + fileName + "</Field>";
            strBatch += "</Method>";
            Batch.InnerXml = strBatch;

            XmlNode returnvalue = listService.UpdateListItems(libraryName, Batch);

            if (returnvalue.InnerXml.Contains("0x00000000"))
            {
                output = "Success: File Deleted";
            }
            else if (returnvalue.InnerXml.Contains("Invalid file name"))
            {
                output = "Failure: No such file exists";
            }
            else if (returnvalue.InnerXml.Contains("Access denied"))
            {
                output = "Failure: No such file exists";
            }
            else
            {
                output = "Failure: File couldn't be deleted";
            }
        }
        catch (SoapException ex)
        {
            throw ex;
        }
        catch (Exception)
        {
            throw ex;
        }
        return output;
    }

    protected int GetFileIdFromList(string siteUrl, string libraryName, string fileName, string serviceUrl)
    {
        int id = 0;

        Lists listService = new Lists(); //Web reference of http://<server>/sites/<site>/_vti_bin/lists.asmx
        listService.Url = serviceUrl;
        listService.UseDefaultCredentials = true;

        // Build the CAML Query
        System.Text.StringBuilder queryStringBuilder = new System.Text.StringBuilder();
        queryStringBuilder.Append("     <Query>");
        queryStringBuilder.Append("         <Where>");
        queryStringBuilder.Append("             <Eq>");
        queryStringBuilder.Append("                  <FieldRef Name=\"FileLeafRef\" />");
        queryStringBuilder.Append("                  <Value Type=\"Text\">" + fileName + "</Value>");
        queryStringBuilder.Append("             </Eq>");
        queryStringBuilder.Append("        </Where>");
        queryStringBuilder.Append("    </Query>");

        XmlDocument query = new XmlDocument();
        query.LoadXml(queryStringBuilder.ToString());

        //Build the View Query 
        queryStringBuilder.Clear(); // Clear the string builder
        queryStringBuilder.Append("    <ViewFields>");
        queryStringBuilder.Append("    <FieldRef Name=\"ID\" /><FieldRef Name=\"Title\" /><FieldRef Name=\"Name\" />");
        queryStringBuilder.Append("    </ViewFields>");

        XmlDocument viewFields = new XmlDocument();
        viewFields.LoadXml(queryStringBuilder.ToString());

        //Build the CAML Query Options
        queryStringBuilder.Clear(); // Clear the string builder
        queryStringBuilder.Append("    <QueryOptions>");
        queryStringBuilder.Append("         <Folder>" + libraryName + "/</Folder> />");
        queryStringBuilder.Append("    </QueryOptions>");

        XmlDocument queryOptions = new XmlDocument();
        queryOptions.LoadXml(queryStringBuilder.ToString());

        XmlNode listItems = listService.GetListItems(libraryName, null, query, viewFields, null, queryOptions, null);

        foreach (XmlNode outerNode in listItems.ChildNodes)
        {
            if (outerNode is XmlWhitespace)
                continue;
            else
            {
                if (outerNode.Name == "rs:data")
                {
                    foreach (XmlNode innerNode in outerNode.ChildNodes.OfType<XmlNode>())
                    {
                        if (innerNode is XmlWhitespace)
                            continue;
                        else
                        {
                            id = Int32.Parse(innerNode.Attributes["ows_ID"].Value.ToString());
                        }
                    }
                }
            }
        }

        return id;
    }