ASP.NET MVC: Creating localized DropDownLists for enums

A collection of HTML helpers that generate DropDownlists for enums, with or without localization support.

Table of contents

 

HTML Helpers Overview

I’ve created a set of HTML helpers that generate a DropDownList for an enum.
Those helpers are similar to DropDownList Method and DropDownListFor Method, with the only difference being that the those helpers will populate the DropDownList with the elements of the specified enum.

 

Some examples – Basic usage

Let’s assume the following model:

public enum WeekDay
{
    Sunday,
    Monday,
    Tuesday,
    Wednesday,
    Thursday,
    Friday,
    Saturday
}

public class WeeklyEvent
{
    public string Title { get; set; }
    public WeekDay Day { get; set; }
    public WeekDay? AnotherDay { get; set; }
}

 

Setting the name of the element and default empty item text

This is the most basic usage, the generated text will be enumValue.ToString():

// name="eventDay"
@Html.EnumDropDownList<WeekDay>("eventDay", "Select an item")

// name="Day"
@Html.EnumDropDownListFor<WeeklyEvent, WeekDay>(x => x.Day, "Select an item")

Html.EnumDropDownListFor works with nullables too:

@Html.EnumDropDownListFor<WeeklyEvent, WeekDay?>(x => x.AnotherDay, "Select an item")

 

Using [Description] attribute

You can customize the text using DescriptionAttribute:

public enum WeekDay
{
    [Description("Domingo")]
    Sunday,

    [Description("Segunda")]
    Monday,

    [Description("Terça")]
    Tuesday,

    [Description("Quarta")]
    Wednesday,

    [Description("Quinta")]
    Thursday,

    [Description("Sexta")]
    Friday,

    [Description("Sábado")]
    Saturday
}

 

Using custom HTML attributes

Just like DropDownList and DropDownListFor, you can use custom HTML attributes

@Html.EnumDropDownList<WeekDay>("eventDay", "Select an item", new { @class="select"})

@Html.EnumDropDownListFor<WeeklyEvent, WeekDay>(x => x.Day, "Select an item" , new { @class="select"})

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ASP.NET: Downloading files from a UNC share

Implementing a cross-browser solution for downloading files from a UNC share in ASP.NET applications

Table of contents

The scenario

I was working recently in an intranet application that had a download page. The output HTML was similar to the following:

<li><a class="download" href="\\MYSERVER\reports 2011\report1.zip" title="Report 1">Report 1</a></li>
<li><a class="download" href="\\MYSERVER\reports 2011\report2.zip" title="Report 2">Report 2</a></li>
<li><a class="download" href="\\MYSERVER\reports 2011\report 3.zip" title="Report 3">Report 3</a></li>
<li><a class="download" href="\\MYSERVER\reports 2011\report 4.zip" title="Report 4">Report 4</a></li>
<li><a class="download" href="\\MYSERVER\reports 2011\report 5&6.zip" title="Report 5&6">Report 5&6</a></li>

This was working fine in IE9, but not in other browsers. There was no action using Google Chrome, and using Firefox there was an error (HTTP Error 400 – Bad Request).

I tried to convert the file path to a file URI but it didn’t fix it. It continued to work on IE only.

<li><a class="download" href="file://MYSERVER/reports 2011/report1.zip" title="Report 1">Report 1</a></li>
<li><a class="download" href="file://MYSERVER/reports 2011/report2.zip" title="Report 2">Report 2</a></li>
<li><a class="download" href="file://MYSERVER/reports 2011/report 3.zip" title="Report 3">Report 3</a></li>
<li><a class="download" href="file://MYSERVER/reports 2011/report 4.zip" title="Report 4">Report 4</a></li>
<li><a class="download" href="file://MYSERVER/reports 2011/report 5&6.zip" title="Report 5&6">Report 5&6</a></li>

The solution was to create a custom ASP.NET download page. I used also jquery on the client side.

Step 1: Using jquery on the client side

The first step was to add an event handler to the download links. The request URI is encoded and is sent as a parameter to the download page. Creating an hidden iframe and setting the src attribute with the download link allows the file to be downloaded asynchronously.

$("a.download").bind("click", function (e) {
    e.preventDefault();
    var requestedFile = encodeURIComponent($(this).attr('href'));

    var iframe = document.createElement("iframe");
    iframe.src = 'Download.aspx?file=' + requestedFile;
    iframe.style.display = "none";
    document.body.appendChild(iframe); // triggers download page
});

Make sure you use encodeURIComponent function to encode special characters in the filename.

Step 2: Create an ASP.NET download page

This is the source code of the download page:

protected void Page_Load(object sender, EventArgs e)
{
    try
    {
        string requestFile = Request.QueryString["file"];

        if(string.IsNullOrEmpty(requestFile))
        {
            throw new FileNotFoundException("File to download cannot be null or empty");
        }

        // Get file name from URI string in C#
        // http://stackoverflow.com/a/1105614
        var uri = new Uri(requestFile);
        string filename = Path.GetFullPath(uri.LocalPath);
        var fileInfo = new FileInfo(filename);

        if(!fileInfo.Exists)
        {
            throw new FileNotFoundException("File to download was not found", filename);
        }


        // get content type based on file extension. Example:
		// http://stackoverflow.com/a/691599
        Response.ContentType = GetContentType(fileInfo.Extension);

        Response.AddHeader("Content-Disposition", 
                           "attachment; filename=\"" + fileInfo.Name + "\"");
        Response.WriteFile(fileInfo.FullName);
        Response.End();
    }
    catch(ThreadAbortException)
    {
        // ignore exception
    }
    catch(FileNotFoundException ex)
    {
        Response.StatusCode = (int) System.Net.HttpStatusCode.NotFound;
        Response.StatusDescription = ex.Message;
    }
    catch(Exception ex)
    {
        Response.StatusCode = (int) System.Net.HttpStatusCode.InternalServerError;
        Response.StatusDescription = string.Format("Error downloading file: {0}", ex.Message);
    }
}

Some notes:

This is necessary in order to make the download work with a UNC share (\\MYSERVER\….) or a file URI (file://….)

    var uri = new Uri(requestFile);
    string filename = Path.GetFullPath(uri.LocalPath);

To avoid filename truncating, it’s necessary to wrap the filename with quotes

    Response.AddHeader("Content-Disposition", 
                       "attachment; filename=\"" + fileInfo.Name + "\"");

References

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