Read a HTML file into a string variable in memory

Question

If I have a HTML file on disk, How can I read it all at once in to a String variable at run time? Then I need to do some processing on that string variable.

Some html file like this:

<html>
    <table cellspacing="0" cellpadding="0" rules="all" border="1" style="border-width:1px;border-style:solid;width:274px;border-collapse:collapse;">
        <COLGROUP><col width=35px><col width=60px><col width=60px><col width=60px><col width=59px></COLGROUP>
        <tr style="height:20px;">
            <th style="background-color:#A9C4E9;"></th><th align="center" valign="middle" style="color:buttontext;background-color:#D3DCE9;">A</th><th align="center" valign="middle" style="color:buttontext;background-color:#D3DCE9;">B</th><th align="center" valign="middle" style="color:buttontext;background-color:#D3DCE9;">C</th><th align="center" valign="middle" style="color:buttontext;background-color:#D3DCE9;">D</th>
        </tr><tr style="height:20px;">
            <th align="center" valign="middle" style="color:buttontext;background-color:#E4ECF7;">1</th><td align="left" valign="top" style="color:windowtext;background-color:window;">Hi</td><td align="left" valign="top" style="color:windowtext;background-color:window;">Cell Two</td><td align="left" valign="top" style="color:windowtext;background-color:window;">Actually a longer text</td><td align="left" valign="top" style="color:windowtext;background-color:window;">Final Word</td>
        </tr>
    </table>
</html>

score 69 · Accepted Answer · edited Jul 06 '17 at 13:18

69

Use File.ReadAllText passing file location as an argument.

However, if your real goal is to parse html then I would recommend using Html Agility Pack.

edited Jul 06 '17 at 13:18

Eonasdan

7,563
8
55
82

answered Aug 29 '12 at 18:07

empi

15,755
8
62
78

4

Do not forget to check if the file exists before you read in the file. :) – TGarrett Nov 18 '16 at 13:18
HAP did it for me! – Harold_Finch Nov 12 '18 at 07:47

score 25 · Answer 2 · answered Aug 29 '12 at 18:07

25

Use System.IO.File.ReadAllText(fileName)

answered Aug 29 '12 at 18:07

L.B

114,136
19
178
224

score 19 · Answer 3 · answered Aug 29 '12 at 18:07

19

string html = File.ReadAllText(path);

answered Aug 29 '12 at 18:07

Forte L.

2,772
16
25

score 13 · Answer 4 · answered Oct 21 '14 at 12:57

13

This is mostly covered already, but one addition as I ran into an issue with the previous code samples.

Dim strHTML as String = System.IO.File.ReadAllText(HttpContext.Current.Server.MapPath("~/folder/filename.html"))

answered Oct 21 '14 at 12:57

s15199d

7,261
11
43
70

score 5 · Answer 5 · answered Aug 29 '12 at 18:10

5

Use File.ReadAllText(path_to_file) to read

answered Aug 29 '12 at 18:10

Srijan

1,234
1
13
26

score 4 · Answer 6 · edited Jun 25 '16 at 02:58

4

What kind of processing are you trying to do? You can do XmlDocument doc = new XmlDocument(); followed by doc.Load(filename). Then the XML document can be parsed in memory.

Read here for more information on XmlDocument:

edited Jun 25 '16 at 02:58

Stacked

6,892
7
57
73

answered Aug 29 '12 at 18:09

Ted Spence

2,598
1
21
21

score 4 · Answer 7 · answered Nov 20 '18 at 00:50

4

You can do it the simple way:

string pathToHTMLFile = @"C:\temp\someFile.html";
string htmlString = File.ReadAllText(pathToHTMLFile);

Or you could stream it in with FileStream/StreamReader:

using (FileStream fs = File.Open(pathToHTMLFile, FileMode.Open, FileAccess.ReadWrite))
{
    using (StreamReader sr = new StreamReader(fs))
    {
        htmlString = sr.ReadToEnd();
    }
}

This latter method allows you to open the file while still permitting others to perform Read/Write operations on the file. I can't imagine an HTML file being very big, but it has the added benefit of streaming the file instead of capturing it as one large chunk like the first method.

answered Nov 20 '18 at 00:50

vapcguy

7,097
1
56
52

*This latter method allows you to open the file while still **permitting** others to perform **Read/Write** operations on the file*. Are you implying the first method **prohibits** others to perform **Read** operations on the file? Because I don't suppose so. – om-ha Jan 04 '20 at 07:57
Waiting for your response @vapcguy – om-ha Jan 04 '20 at 07:59
1

@om-ha Wasn't trying to imply that at all - honestly, I never tested reading and writing operations at the same time while doing a `File.ReadAllText`. I have tested it with multiple combinations of the latter code block, however. I only meant it as a description for what is in that last block of code because there are various options to use with `FileMode` and `FileAccess` that don't actually work that you might think actually would. – vapcguy Jan 06 '20 at 08:00

score 1 · Answer 8 · answered Nov 16 '20 at 16:45

1

var htmlText = System.IO.File.ReadAllText(@"C:/filename.html");

And if file in at application root, user below

var htmlText = System.IO.File.ReadAllText(HttpContext.Current.Server.MapPath(@"~/filename.html"));

answered Nov 16 '20 at 16:45

Shakoor Hussain Attari

1,641
13
8

Read a HTML file into a string variable in memory

8 Answers8