Open folder and decide which file to use C#

Question

Open folder and decide which file to use C#

Sela 126

Dear Sir or Madam,

I have a question for you. I have a folder with my own generated text files, each with the same extension but with different names. In order to improve the use of the files I would like to open the folder with the programming language C#. the folder and decide which file I would like to use in further processing. Currently the whole thing happens manually by always entering the respective path name, I don't want to solve it that way anymore. (There are always other generated files coming into the folder).
Many thanks in advance.

With kind regards,
Sela

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Answer 1

Michael Taylor 60,326

I'm not sure I completely follow the problem you're trying to solve but it sounds like you want to select a file in your C# app. You didn't mention what type of app it is but only a Windows UI would allow you to select from a graphical UI. To do that you would use the OpenFileDialog. Something like this.

   private string SelectFile ()  
   {  
      var dlg = new OpenFileDialog() {  
          InitialDirectory = "your default path you want to use, if any",  
          Filter = "Text Files (*.txt) | *.txt | All Files (*.*) | *.*",  
          RestoreDirectory = true        
      };  
     
      //User didn't select a file so return a default value  
      if (dlg.ShowDialog() != DialogResult.OK)  
         return "";  
     
      //Return the file the user selected  
      return dlg.FileName;  
   }

For a console application you would need to retrieve the files in the directory(ies) you care about and display some sort of menu or something, depending upon what you needed.

Sela 126 Reputation points

2022-03-02T16:32:08.93+00:00

Yes exactly, that's about how I have it. Now my question was how do I select the desired file to use it.
Michael Taylor 60,326 Reputation points

2022-03-02T16:37:15.813+00:00

What do you mean by "select" the file to use? What do you intend to do with it?

The FileName property of the dialog has the full path to the file so if you need the file path then that has it. If you want to open the file for reading or something then it depends upon how big the file is and what your intentions are: read only, write, parse, etc.
Sela 126 Reputation points

2022-03-02T16:46:58.277+00:00

So I have several text files in my folder, however I only need one of them to send to the PLC. That's why I thought that I open the file and check if the file is there. After the check, the desired file is selected and forwarded to the PLC.
Michael Taylor 60,326 Reputation points

2022-03-02T16:52:28.133+00:00
Out of the box PLCs don't understand files. If you're using OPC's file server functionality then all you need is the file path.

If your PLC needs the text out of the file then you can get that using the following code.

string text = File.ReadAllText(filepath);

This returns you the entire contents of the file. Note however that the file will have Windows CRLF for newlines. That probably isn't going to work in the PLC so you'll need to replace the newlines with what the PLC expects.

Alternatively you can read the file as separate lines and then join them with the newline character(s) needed by the PLC.

string text = String.Join("newlineforplc", File.ReadAllLines(filepath));

Answer 2

Going with @Michael Taylor reply, do you want to pre-select a file? If so than consider the following. All I've added was FileName set to whatever file you would want pre-selected and exists.

var dlg = new OpenFileDialog()  
{  
    InitialDirectory = "our default path you want to use",  
    Filter = "Text Files (*.txt) | *.txt | All Files (*.*) | *.*",  
    RestoreDirectory = true,   
    FileName = "File to pre select goes here that resides in InitialDirectory"  
};  
  
if (dlg.ShowDialog() == DialogResult.OK )  
{  
    //  
}  
else  
{  
    //  
}

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Open folder and decide which file to use C#

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