Néstor Requesens Godó

Enable/Disable Asp.net validatiors using JavaScript

2010-03-25T02:36:00.000-07:00

ASP.NET provides predefined validators for controls in ASP.NET pages:

RequiredFieldValidator
RegularExpressionValidator
...

These validation controls offer the server-side property "Enabled" to be able to Enable/Disable them from server-side code. But what if we want to Enable/Disable them in client-side code (Javascript): Then there is a predefined JS method: ValidatorEnable(ValidatorId, Boolean); which allows us to do so.

To enable a control we would do like:
ValidatorEnable(document.getElementById('<%= validatorUserName.ClientID %>'), true);

And to disabe it:
ValidatorEnable(document.getElementById('<%= validatorUserName.ClientID %>'), false);

Couldn't it be easier?

Code to change SPListItem permissions with a non-full-control user

2010-03-17T02:50:00.001-07:00

Recently I faced the need to change SharePoint's List Items permissions programmatically. The tricky part of it was the fact that the user performing the action had only contributor rights on the site. The workaround to perform such action is to run the code as a user with elevated privileges. So here is my first approach:

Guid SiteId = SPContext.Current.Site.ID;
Guid WebId = SPContext.Current.Web.ID;

SPSecurity.RunWithElevatedPrivileges(delegate()
{
using (SPSite ElevatedSite = new SPSite(SiteId))
{
using (SPWeb ElevatedWeb = ElevatedSite.OpenWeb(WebId))
{
//Code to change permissions
}
}
});

Using this code, at the moment you execute the sentences to change the permissions, you get an error like: "The security validation for this page is invalid". The way to solve this error is to set the AllowUnsafeUpdates property to true for the SPWeb object and validate the form digest control used in the current request. Hence the code snippet will look like this:

Guid SiteId = SPContext.Current.Site.ID;
Guid WebId = SPContext.Current.Web.ID;

SPSecurity.RunWithElevatedPrivileges(delegate()
{
using (SPSite ElevatedSite = new SPSite(SiteId))
{
using (SPWeb ElevatedWeb = ElevatedSite.OpenWeb(WebId))
{
ElevatedWeb.AllowUnsafeUpdates = true;
ElevatedWeb.Update();
SPUtility.ValidateFormDigest();

//Code to change permissions

ElevatedWeb.AllowUnsafeUpdates = false;
}
}
});

And finally the code to change the permissions would look some thing like this:

listItem.BreakRoleInheritance(false);
SPRoleAssignment role = new SPRoleAssignment(SPContext.Current.Web.EnsureUser("SOMEUSERorGROUP"));
role.RoleDefinitionBindings.Add(ElevatedWeb.RoleDefinitions.GetByType(SPRoleType.Contributor)); //Or any other SPRoleType
listItem.RoleAssignments.Add(role);
listItem.Update();

This worked for me. Hope it helps!

SharePoint Full Error Messages

2010-03-15T08:26:00.000-07:00

While testing a SharePoint app, it is useful to see the "real" error messages instead of the nice "An unknown error occured. Please contact your system administrator".

As I'm always forgetting how to set the web.config to show the "real" errors, here are the couple of steps which need to be done:

Switch custom errors off
<system.web>
…
<customErrors mode="Off" />
…
</system.web>
Enable CallStack
<SharePoint>
…
<SafeMode CallStack="true" />
…
</SharePoint>

Solution to: Cannot convert type 'Microsoft.SharePoint.WebControls.ScriptLink' to 'System.Web.UI.IAttributeAccessor'

2010-03-11T08:18:00.000-08:00

An error occurred during the processing of . http://server/_catalogs/masterpage/YOURMASTER.master(18): error CS0030: Cannot convert type 'Microsoft.SharePoint.WebControls.ScriptLink' to 'System.Web.UI.IAttributeAccessor'

When deploying and setting a customized master page to a SharePoint site collection through a feature, after the deployment of the solution and feature activation success, you can end up having the above listed error.

I guess this error might be caused for several reasons. But if you use SharePoint Designer to customize the master page and then Export option to export it into a file, SharePoint Designer adds a lot of non-sense code to the file.

In order to solve the error, you just have to copy & paste the code into a new text file and save this file as your new master page to deploy.

Hope it helps.

Upload multiple files attached to a SharePoint list item.

2010-01-22T05:20:00.000-08:00

Recently I faced the need of programming a control for uploading multiple files attached to a SharePoint list item. Following this video example I could easily create an ASP.NET control to upload multiple files to a web server. Then I just addapted the code to upload the files attached to the SharePoint list item and the final result is as follows:

SPWeb mySite = SPContext.Current.Web;
SPList myList = mySite.Lists["myList"];
SPListItem myListItem = myList.Items.Add();

myListItem["Title"] = "myTitle";
...

if (HttpContext.Current.Request.Files.Count > 0)
{
HttpFileCollection uploads = HttpContext.Current.Request.Files;
SPAttachmentCollection attachments;

for (int i = 0; i < uploads.Count; i++)
{
Stream fs = uploads[i].InputStream;
byte[] fileContents = new byte[fs.Length];
fs.Read(fileContents, 0, (int)fs.Length);
fs.Close();
attachments = myListItem.Attachments;
string fileName = Path.GetFileName(uploads[i].FileName);
attachments.Add(fileName, fileContents);
}
myListItem.Update();
}

I hope this helps!

Trying to use an SPWeb object that has been closed or disposed and is no longer valid.

2010-01-21T09:08:00.000-08:00

Developing in SharePoint you can come across this error (Trying to use an SPWeb object that has been closed or disposed and is no longer valid) for so many reasons.

The one I faced today was because I was using a SPWeb object initialized to the current context, so something like:

SPWeb site = SPContext.Current.Web

In order to skip the Dispose statement I wrapped the my code into a using block, so I had something like:

using (SPWeb site = SPContext.Current.Web)
{
...
}

The problem is that when we execute SPWeb site = SPContext.Current.Web, an object is not actually created and the site variable only gets a reference to the existing object, which in this particular case is the current context. Then at the end of the using block, the code will actually dispose the current context, which is a non-desirable efect.

So in order to avoid this error, just don't try to dispose the current context!

You can read more info about all that in: Best Practices: Using Disposable Windows SharePoint Services Objects (http://msdn.microsoft.com/en-us/library/aa973248.aspx)

SharePoint Web Part Maintenance Page

2010-01-21T03:14:00.001-08:00

For some reason I never remember this: If you have a SharePoint web part which causes a problem on a page and it prevents it from loading, you can always browse to the web part maintenance page, which allows you to close, reset and delete web parts from a particular page.

The way to browse into the web part maintenance page is adding ?contents=1 to the end of the page's url. For example: http://mysharepointsite/default.aspx?contents=1.

How to set the parent content type when deploying a content type as a feature?

2010-01-05T02:17:00.001-08:00

Out there you can find lots of articles explaining how to deploy a SharePoint content type as a feature, but one thing I found difficult to find out was how to set which has to be the parent content type of the content type we want to deploy. This post is not meant to explain how to deploy a CT as a SharePoint feature, it’s just to point out how to set the parent.

Normally if we deploy a content type as a feature we will have something like this in our XML:

Looking at the Content Type ID of this example we have: 0x010100928100FAB05A4148BD6F4C8E6A716B40. This Id has two parts separated using a 00. The first part of the Id (0x0101) is the Id of the parent content type (document in this case) and the second part of the Id is the Id we need to generate for the content type we want to deploy.

There are several ways to find out the Id of a content type. An easy one is to copy from the URL bar when we are in the Site Content Type Information screen coming from the site content type gallery. (Site actions -> Site settings -> Site content types -> “click on the desired CT”).

Hope this helps.

STSADM -o export: FatalError: Failed to compare two elements in the array

2009-12-09T04:44:00.001-08:00

In MOSS 2007, if you use STSADM to export a Site Collection you may face an error like that in the resulting log file:

... FatalError: Failed to compare two elements in the array. Which doesn't help so much in solving the problem.

Finally today, while Googleing for the solution I found this post in MVP Steven Van de Craen's Blog, which explains the cause and how to solve the problem.

Briefly, the cause is an invalid Feature registration in the Site Collection or root Site which you are trying to export. And the solution is deactivate the “failing feature” with the help of this nice tool which finds and enumerates invalid features.

Paging in LINQ

2009-08-20T09:45:00.001-07:00

LINQ makes really easy the paging of a result set. No more writing complex logic to page results of our queries. We can easily page using the methods Skip and Take.

The Take method is used to indicate how many results are going to be fetched, like the TOP keyword in SQL. Here is an example:

List<Movie> movies = GetMovieList();
var takenMovies = (from m in movies select new {m.Name, m.Director} ).Take(4);

As you can imagine, the Skip method is used to indicate how many results we want to skip from the top. So the combination of both methods gives us a pretty easy way to perform paging. Here is an example which takes Movies from 8^th to 11^th:

List<Movie> movies = GetMovieList();
var takenMovies = (from m in movies select new {m.Name, m.Director} ).Skip(7).Take(4);

Hope you find it useful.

LINQ's Intesect method using IEqualityComparer

2009-08-19T03:22:00.000-07:00

The Intersect method produces the set intersection of two sequences by using the specified IEqualityComparer<(Of <(T>)>) to compare values. Here comes an example on how to use it.

The first thing we do in this example is implement the class we want to compare. For this example is going to be “Project”:

public class Project
{

public string ProjectName { get; set; }
public string ShortDescription { get; set; }

}

Secondly we must implement the comparer class which it’s going to inherit from IEqualityComparer<Project>. If we write the header of the class and right-click the interface name, Visual Studio is going to write the method headers we need to implement (Equals and GetHashCode). The implementation which comes is just an example on how to do it:

public class ProjectComparer : IEqualityComparer<Project>
{

public bool Equals(Project x, Project y)
{

// Check whether the compared objects reference the same data.
if (Object.ReferenceEquals(x, y)) return true;

// Check whether any of the compared objects is null.
if (Object.ReferenceEquals(x, null) || Object.ReferenceEquals(y, null)) return false;

// Check whether the products' properties are equal.
return (x.ProjectName == y.ProjectName && x.ShortDescription == y.ShortDescription );

}

public int GetHashCode(Project obj)
{

// Check whether the object is null.
if (Object.ReferenceEquals(obj, null)) return 0;

// Get the hash code for the ProjectName field if it is not null.
int hashProjectName = obj.ProjectName == null ? 0 : obj.ProjectName.GetHashCode();

// Get the hash code for the ShortDescription field if it is not null.
int hashShortDescription = obj. ShortDescription == null ? 0 : obj.ShortDescription.GetHashCode();

return hashProjectName ^ hashShortDescription;

}

Once we have the class to compare and the comparer, we are ready to use the Intersect method like this:

listOfProjects = listOfProjectsA.Intersect(listOfProjectsB, new ProjectComparer()).ToList();

In this example of execution listOfProjects is going to have the elements of the Project class which are in listOfProjectsA and listOfProjectsB.

Hope this helps!

How to reset the identity of a table in SQL Server

2009-08-17T07:41:00.000-07:00

Recently I faced the problem which drove me to remove all the values from a table which has an identity column. Once I inserted the new values I realized that these new values identities were starting at the last identity of the old rows I already deleted. The way to reset the identity counter” of a table is reseeding it using the following: DBCC CHECKIDENT('TableName', RESEED, Seed).

SQL "IN" clause in LINQ

2009-08-13T06:32:00.001-07:00

I’ve been searching how to implement the SQL IN clause in LINQ and finally I got it.

You have to use the Contains method on the collection which is actually holding all the values you want to be compared by the IN clause. Here comes an example:

LINQ code:

int[] values = { 1, 2, 3 };
using (DataContext dc = new DataContext("…"))
{
var std =
(from stds in dc.Standards
where values.Contains(stds.StandardId)
select stds
);
}

SQL Equivalent:

SELECT * FROM Standards WHERE StandardId IN (1, 2, 3)

Hope this helps!

Embedding JW FLV Player to Umbraco through XSLT

2009-07-08T00:17:00.000-07:00

Here comes an XSLT macro for umbraco which makes quite easy to embed the JW FLV Player to an umbraco page:

<xsl:stylesheet …

<xsl:param name="currentPage"/>

<xsl:template match="/">

<xsl:variable name="urlVideo" select="umbraco.library:GetMedia($currentPage/data [@alias='myVideo'], 0)/data [@alias = 'umbracoFile']"/>

<xsl:if test="$urlVideo != ''">

var s1 = new SWFObject('/ClientBin/player.swf','player','468','350','9');

s1.addParam('allowfullscreen','true');

s1.addParam('allowscriptaccess','always');

s1.addParam('flashvars','file=<xsl:value-of select='$urlVideo'></xsl:value-of>');

s1.write('preview');

</script>

</xsl:if>

</xsl:template>

</xsl:stylesheet>

Note that this macro must be included into a template associated to a document type which has myVideo as a Media property with the video we want to play.

Hope you find it useful.

Umbraco XSLT - Check empty node sets

2009-06-29T07:43:00.000-07:00

Using the string function is the easiest and fastest way to check if a node set is empty or not in an umbraco XSLT macro. Here comes a quick example:

<xsl:template name="drawStuff">

<xsl:param name="pag"/>

<xsl:if test="string($pag)">

</xsl:if>

</xsl:template>

Managed properties + Search Scopes in Search Server 2008

2009-05-13T03:15:00.000-07:00

Just now I found the way to improve search scopes in Search Server 2008. The thing is: you can enable a Managed Property to act as filter in a search scope. Here are the steps you must do in order to configure a search scope rule for doc files:

1. Open Search Server Administration

2. Click Queries and Results à Metadata Properties

3. Here is where you can add or edit managed properties: For the example we will edit the FileExtension property and we will check in the “Allow this property to be used in scopes” option.

4. Then we head to create a new scope and we add a rule like this:

I hope this helps…

Adding "normal" aspx pages to umbraco sites

2009-04-23T00:23:00.000-07:00

Developing web portals in umbraco, we might get the need of including “normal” aspx pages in our site. What I mean by “normal” aspx pages are pages which don’t get served by umbraco (i.e: a custom web form).

Well then, in order to do this, umbraco has the umbracoReservedUrls and the umbracoReservedPaths settings in the web.config file. The first one allows us to reserve single files and using the second one we’ll be able to reserve folders.

Here is an example for both:

Hope this helps!

Interesting Web Parts for SharePoint

2009-03-11T02:12:00.000-07:00

Thanks to Footprint of IT I found some interesting and free web parts for Windows SharePoint Services 3.0. Among others, there are web parts that allow us to add interactive charts or slideshows to our SharePoint sites. You can check them out at: http://www.spelements.com/

Interesting Video: Building Master Pages for WSS 3.0 using Site Definitions in Visual Studio

2009-02-18T10:34:00.000-08:00

While performing some research in how to build master pages for WSS I found this illustrative video (7 min.) in MSDN, which shows how to build a WSS master page using a site definition created in Visual Studio 2005.

Here is the link to the full MSDN article.

Hope this helps...

Feeding a Sharepoint Navigation Provider with a XML file

2009-02-18T07:53:00.000-08:00

Depending on how we implement a portal in Sharepoint (WSS or MOSS) we might need special sources for our navigation menus. My approach in this is to feed them with XML files in order to have the maximum flexibility in the navigation.

The first think we must do is adding a new XmlContentMapProvider provider in our web.config. Here is an example:

</providers>

</siteMap>

Then we have to configure a new site map, adding the file mainMenu.sitemap, here is where the XML souce comes:

</siteMapNode>

</siteMap>

We can place the mainMenu.sitemap file wherever we want to place it, but we must do it according to the siteMapFile attribute we added in the web.config new provider. For this example I used: inetpub/wwwroot/wss/virtualdirectories/myportal/_app_bin/.

Now we only have to modify the master page (default.master):

· Add this code inside a SharePoint:DelegateControl next to the topSiteMap:

<asp:SiteMapDataSource
ShowStartingNode="true"
SiteMapProvider="CustomXmlContentMapProvider"
id="xmlSiteMap"
runat="server"/>

Change the datasource of the Sharepoint:AspMenu with ID=TopNavigationMenu from topSiteMap to xmlSiteMap.

umbraco 4.0 running over .NET framework 3.5

2009-02-09T23:38:00.000-08:00

I’ve been a couple of days trying, with no success, to get to work umbraco 4 over a Windows Server 2003 with the .NET framework 3.5. Finally today, at the umbraco’s codeplex releases page, they posted a PDF showing how to run umbraco on 3.5. The only important thing in that document is the link to a new web.config special for 3.5.

Probably I’ll start working with umbraco in some days. I hope to get the time to blog some of my experiences…

Writing a global error handler in ASP.NET

2009-01-22T15:10:00.000-08:00

In this first article I’d like to show the way I use to control the global exceptions or errors in an ASP.NET application. Most of the times we might be keen on customizing error messages in order to avoid the typical ASP.NET Internal Server Error page.

The first thing we must do is edit the customErrors node in our ASP.NET web.config XML file in order to avoid the detailed information about the errors. Here is an example:

Web.config:

<customErrors mode="RemoteOnly" defaultredirect="AppErrors.aspx">
<error statuscode="404" redirect="ThereIsNoPage.aspx"> 
</customErrors>

Then we must implement with the desired code the Application_Error function in the global.asax code file. Here is a simple example which only grabs some error info, passes it to a customized error page (through Session) and it finally navigates to this page.

Global.asax:

 Exception ex = Server.GetLastError().GetBaseException();
 Session[CT.ERR_MESS] = ex.Message;
 Session[Ctants.SESSIO_ERROR_STACKTRACE] = ex.StackTrace;
 Server.Transfer("Errors.aspx");

Errors.aspx.cs:

protected void Page_Load(object sender, EventArgs e)
  {
     if (Session[CT.ERR_MESS] != null)
     {
     lblErrorMessage.Text += Session[CT.ERR_MESS].ToString();
        Session.Remove(CT.ERR_MESS);
     }
     if (Session[CT.ERR_STACK] != null)
     {
        lblErrorStack.Text += Session[CT.ERR_STACK].ToString();
        Session.Remove(CT.ERR_STACK);
     }
}

Hope this helps…

Hello World

2009-01-22T15:07:00.000-08:00

After some time working in Itequia as a Software Engineer, I finally get the time to start blogging about the stuff I almost deal every day.

Here you will find my thoughts about software and other IT matters. In the beginning my posts will be about some Microsoft technologies like .NET or SharePoint, as those are the ones which I’m working now.

I hope you find it interesting…