how to replace the content of a file and then save the new file

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hi. i am creating a win form. in my form i have added do while loop.. i have added TABLE LAYOUT PANEL ..in this, the text box is declared and it creates text boxes inside the layout panel.. but my problem is i can read file but if i want to change the text written in text box, i am not able to save the file.. i want to replace the old content of a file and then overwrite it..plz help me

Posted 15-May-13 0:32am

shashank 1068

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ZurdoDev 15-May-13 7:19am

What does table layout panel have to do with saving a file? You need to post relevant code.

shashank 1068 15-May-13 13:00pm

Dim path As String = "c:\temp\MyTest.txt"

Try
Dim sr As StreamReader = New StreamReader(path)
Dim line As String = ""

Do While sr.Peek() >= 0
line = sr.ReadLine()
Dim newTextBox As TextBox = New TextBox()
newTextBox.Text = line
Panel1.Controls.Add(newTextBox)
Loop
sr.Close()
Catch e As Exception
Console.WriteLine("The process failed: {0}", e.ToString())
End Try
End Sub
this is my code for displaying data in textbox
but if i want to modify the tex in textbox
so i want to save the data after writing new text in textbox

ZurdoDev 15-May-13 13:29pm

I would suggest what was suggested in Solution 1.

shashank 1068 15-May-13 13:37pm

u mean bout this code??
File.WriteAllLines(path, myTextBox.Lines)

ZurdoDev 15-May-13 13:38pm

Yes, just use 1 textbox.

shashank 1068 15-May-13 13:44pm

but i dont want to add any textbox
i want to display textbox according to text stored in file
suppose there are 20 URL so it should display 20 textbox

ZurdoDev 15-May-13 13:46pm

But why do you want that many textboxes? Why don't you add them all to one textbox?

shashank 1068 15-May-13 13:49pm

coz i want that each URL should be displayed in each textbox

ZurdoDev 15-May-13 14:17pm

You aren't answering the question. You could do this all in a single textbox. However, you'll need to loop through the textboxes and write their contents to the file. Just set the IDs on the textboxes that you are creating. For example, name them TextBox1, TextBox2, etc, and then you can use FindControl to loop through them all.

shashank 1068 15-May-13 14:23pm

hmmm ohk thnx fr the info. i'll try dis

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OriginalGriff · Answer 1 · 2013-05-15T01:03:00

Solution 1

I assume that you do something like read each line from the file into a separate TextBox?
If so, then you need to loop through all the Textboxes in the panel (you can use its Controls collection to access them) and write each line back to a separate file.

But the question is: why are you doing that? Why not just set a single TextBox to MultiLine=true and use that for the whole file? Then it is just a case of:

VB

myTextBox.Lines = File.ReadAllLines(path)

And

VB

File.WriteAllLines(path, myTextBox.Lines)

Posted 15-May-13 1:03am

OriginalGriff

Comments

shashank 1068 15-May-13 7:09am

actually i want that the textbox should b displayed according to the content present in the file..suppose a file is having 20 URL so it should display only 20 textbox... so for this i have added loop...
but now i want to save the file like if i change any content of textbox i want to replace the older file and overwrite the new file

OriginalGriff 15-May-13 7:13am

So loop through them, and write it out.
What part of that is giving you difficulty?

shashank 1068 15-May-13 7:15am

saving part...
i don't know how to save because in this the textbox is not declared..
i am not having textbox id or name
so i am facing problem in saving part

OriginalGriff 15-May-13 7:23am

So as I said: use the panels Controls property to access all the controls it contains.
Cast them to TextBoxes and you have them ready to rock'n'roll.

shashank 1068 15-May-13 10:47am

i have used table layout panel
i am able to read the file but i am not able to save them

OriginalGriff 15-May-13 11:02am

Ok, let's do this in easy stages.
Do you know how to work your way through the panels Controls collection?

shashank 1068 15-May-13 11:03am

i know how to work on TABLE LAYOUT PANEL

shashank 1068 15-May-13 11:27am

plz tell me what to do now??

OriginalGriff 15-May-13 11:49am

So, iterate through the panel.Control collection - use a For Each loop.
For Each c As Control In myLayoutPanel.Controls
Dim tb As TextBox = TryCast(c, TextBox)
If tb IsNot Nothing Then
... use the textbox here.
End If
Next

Does that do what you need?

shashank 1068 15-May-13 11:56am

after dis can i able to save the new file??

OriginalGriff 15-May-13 12:18pm

This is getting the data you want to save.
I had assumed you knew how to write it to a file - was I mistaken?

shashank 1068 15-May-13 12:31pm

act. i am new with vb.net so its little bit difficult fr me

OriginalGriff 15-May-13 14:01pm

OK, there are a couple of ways to do it.
Are you familiar with File Streams? Or with Lists of strings?

shashank 1068 15-May-13 14:01pm

yes!!

OriginalGriff 15-May-13 14:20pm

Which? You can use both.

Stream:
Open a FileStream to wrote the file, using FileMode.Create
Create a StreamWriter to "wrap" the stream.
In the foreach loop above, use the StreamWriter.WriteLine method to output the Text property of each TextBox.
Close and dispose the StreamWriter and FileStream

Lists:
Create a new List of strings.
In the for each loop above, add each Textbox.Text property to the List.
After the loop ends, use File.WriteAllLines(path, yourList) to output all the values at once.

Does that make sense?

shashank 1068 15-May-13 14:25pm

mmmmm thnx alot i'll try dis

OriginalGriff 15-May-13 14:40pm

You're welcome!