MVC Razor view 'System.OutOfMemoryException' with large value string

Question

I have a big JSON object which I need to pass to the view displayed in web browser. Since I can not have a Controller with an Action to return this JSON object, I thought to add the JSON object in the Razor view.

1. @Html.Hidden("fileContent", fileContent);

2. <textarea style="display:none"> @fileContent </textarea>

None of the above works as the ways I expected and gives me,

Exception of type 'System.OutOfMemoryException' was thrown.

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.OutOfMemoryException: Exception of type 'System.OutOfMemoryException' was thrown.

Yes, I agreed that's better to restructure the flow in another way (may be as Mediator suggest or have an action to return the JSON object.)

1. Is that a limitation of MVC, the maximum size we can have for a MVC view?
2. Is this because of the IIS Express configuration?
3. Any other way to overcome this issue? Or the best way to pass a large object to the client browser.

Thank you for your time. Any help would be highly appreciated.

EDIT

Controller

var file = System.IO.File.ReadAllText(HttpContext.Server.MapPath("~/content/data.csv"));
ViewData.Add("file", file);
return View();

Stack trace

[OutOfMemoryException: Exception of type 'System.OutOfMemoryException' was thrown.] System.Text.StringBuilder.ExpandByABlock(Int32 minBlockCharCount) +163 System.Text.StringBuilder.Append(Char* value, Int32 valueCount) +82
System.Text.StringBuilder.AppendHelper(String value) +31
System.Text.StringBuilder.Append(String value) +186
System.IO.StringWriter.Write(String value) +30
System.Web.WebPages.WebPageBase.Write(Object value) +87

Answer 1

Depending on your CSV file size, better to use ReadLines than ReadAllText like below:

var sb = new StringBuilder();
sb.Capacity = 16; // default, adjust it to less number as you wish

foreach (String line in System.IO.File.ReadLines(HttpContext.Server.MapPath("~/content/data.csv")))
{
    sb.Append(line);    
}

ViewData.Add("file", sb.ToString());

ReadLines returns IEnumerable<String> that reads a file line by line (one line at a time), hence it is suitable for certain files which potentially consuming huge memory space when stored as single large string.

However, if file contents are extremely large, consider using StreamReader instead of StringBuilder which requires contiguous array size and depends on heap fragmentation:

using (var sr = new System.IO.StreamReader(HttpContext.Server.MapPath("~/content/data.csv")))
{
     String line;
     while ((line = sr.ReadLine()) != null)
     {
         // combine source strings here
     }
}

Note that each character requires 2 bytes, and strings are array of characters, thus there should be contiguous arrays which affects performance and size during generating objects in memory. Hence, optimizing garbage collector functionality with GC.Collect() method may helpful after dealing with huge amount of objects requiring immediate cleanup.

Related references:

interesting OutOfMemoryException with StringBuilder

MSDN: System.Text.StringBuilder

MSDN: System.IO.StreamReader

Eric Lippert: Out Of Memory” Does Not Refer to Physical Memory