Windows 7 clipboard copy paste operation using C#

Question

I'm working on a Windows application where I need to use clipboard data. I am trying to copy text from clipboard by the code below.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Threading;

namespace MultiValuedClipBoard
{
    class Class1
    {

        public String SwapClipboardHtmlText(String replacementHtmlText)
        {
            String returnHtmlText = "hello";
            if (Clipboard.ContainsText(TextDataFormat.Html))
            {
                returnHtmlText = Clipboard.GetText(TextDataFormat.Html);
                Clipboard.SetText(replacementHtmlText, TextDataFormat.Html);
            }
            return returnHtmlText;
        }
    }
}

Calling the above function by:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Media;

namespace MultiValuedClipBoard
{
    class Program
    {
        static void Main(string[] args)
        {
            Class1 aas = new Class1();
            string a = aas.SwapClipboardHtmlText("chetan");
            Console.WriteLine(a);
            Console.ReadLine();
        }
    }
}

When running this code it gives the output "Hello" which is the default value, not clipboard data.

Well, it would depend on what's in your clipboard, right? Are you sure there is HTML (specifically, data of type HTML) in your clipboard? — JerKimball, Mar 02 '13 at 06:27
I tried above code with TextDataFormat.text also but it doesn't work when clipboard had some text . — Hot Cool Stud, Mar 02 '13 at 06:34

score 2 · Answer 1 · answered Mar 02 '13 at 07:48

2

Your code will not work because of two reasons:

[1] When you say:

if (Clipboard.ContainsText(TextDataFormat.Html))

Here you are basically assuming that the clipboard already contains a text and that too in HTML format, but depending on the values you are setting in the clipboard it doesn't look like you are intending to use the pre-existing clipboard value anywhere in your program. So, this if condition should not be there.

[2] Secondly, you are further trying to set the string "chetan" to the clipboard which is definitely not in HTML format. So,

            Clipboard.SetText(replacementHtmlText, TextDataFormat.Html);

becomes

            Clipboard.SetText(replacementHtmlText, TextDataFormat.Text);

Hence, effectively, your new code becomes something like this:

        String returnHtmlText = "hello";
        //if (Clipboard.ContainsText(TextDataFormat.Html))
        //{
            returnHtmlText = Clipboard.GetText(TextDataFormat.Text);
            Clipboard.SetText(replacementHtmlText, TextDataFormat.Text);
        //}
        return returnHtmlText;

answered Mar 02 '13 at 07:48

Prahlad Yeri

3,567
4
25
55

i tried code suggested by you . But Clipboard.GetText(TextDataFormat.Text) returns null . It means clipboard doesn't have any value but i copied text before running this app . – Hot Cool Stud Mar 02 '13 at 07:59
Sometimes you run into problems related to blocked clipboards, as some other application might be keeping the clipboard locked. See this link: http://stackoverflow.com/questions/930219/how-to-handle-blocked-clipboard-and-other-oddities – Prahlad Yeri Mar 02 '13 at 08:04
It could also be an issue with your Windows-7 securities/permissions. Try this on an XP machine if you have one. – Prahlad Yeri Mar 02 '13 at 08:06
Thanx yeri for your valuable info but don't we have any solution for windows 7 .... – Hot Cool Stud Mar 02 '13 at 08:33
Try adding the [STAThread] attribute above your main function. See second-last answer in this SO thread: http://stackoverflow.com/questions/518701/clipboard-gettext-returns-null-empty-string – Prahlad Yeri Mar 02 '13 at 09:09

David Heffernan · Accepted Answer · 2013-03-02T10:28:25.887

1

Clearly Clipboard.ContainsText(TextDataFormat.Html) evaluates to false. Which means that the clipboard in fact does not contain text in the format you specify.

I changed your program to prove the point:

[STAThread]
static void Main(string[] args)
{
    Clipboard.SetText("boo yah!", TextDataFormat.Html);
    Class1 aas = new Class1();
    string a = aas.SwapClipboardHtmlText("chetan");
    Console.WriteLine(a);
    Console.WriteLine(Clipboard.GetText(TextDataFormat.Html));
    Console.ReadLine();
}

Output:

boo yah!
chetan

edited Mar 02 '13 at 10:28

answered Mar 02 '13 at 09:05

David Heffernan

601,492
42
1,072
1,490

your code works fine but whenever i tried to copy anything from windows clipboard without SetText() it returns null and before this i copied some text in clipboard . My App runs thread which automatically copy content from windows clipboard . – Hot Cool Stud Mar 02 '13 at 17:17
I don't know what that means. – David Heffernan Mar 02 '13 at 17:27
I need whenever i copy some text with cntrl+c i can retrieve that with Clipboard.GetText(TextDataFormat.text) is it possible ??? – Hot Cool Stud Mar 02 '13 at 17:34
yeah i also think so but it doesn't . Try above code without Clipboard.SetText("boo yah!", TextDataFormat.Html); . You will feel like me. – Hot Cool Stud Mar 02 '13 at 17:46
No, you are quite wrong. If the clipboard contains `TextDataFormat.Html` then it will be returned. You code is telling you that the clipboard does not contain `TextDataFormat.Html`. It is accurate when it does so. Read the first paragraph of my answer once more. That describes what is happening. – David Heffernan Mar 02 '13 at 17:48
Finally i m done with my question thanks for making me correct . – Hot Cool Stud Mar 02 '13 at 17:54

Windows 7 clipboard copy paste operation using C#

2 Answers2