VC# 2005 Express Windows Forms: Replacing parameters in a text file with values from textboxes

[J.S.]

Let's say I have a text file with parameters like the following embedded in
the text:

@@Textbox1@@, @@Textbox2@@, etc.

Is it possible to replace the parameters in the text file with values
entered into textboxes in the Windows Forms UI?

Thanks,
J.S.


--

 

[Brendan Green]

foreach (object o in Form1.Controls)
{
if (o is TextBox)
{
String.Replace("@@" + ((TextBox)o).Name + "@@", ((TextBox)o).Text);
}
}

Of course, you'll need to have read in the contents of the file, and write
it back out again once you're finished.

 

[J.S.]

Thanks, Brendan! Does C# have any equivalent to the VB
My.Computer.FileSystem.OpenTextFileReader or
My.Computer.FileSystem.ReadAllText? I have been searching all over MSDN and
Google without much success. It seems that VB is much better covered at
MSDN.

Thanks,
J.S.

 

[J.S.]

StreamReader and File.OpenText sort of worked. They gave me the last line
in the text file.

 

[Jon Skeet [C# MVP]]

Thanks, Brendan! Does C# have any equivalent to the VB
My.Computer.FileSystem.OpenTextFileReader or
My.Computer.FileSystem.ReadAllText? I have been searching all over MSDN and
Google without much success. It seems that VB is much better covered at
MSDN.

Use File.OpenText, or new StreamReader to create a TextReader which
reads data from a file. After that, use TextReader.ReadToEnd to read
the whole file.

 

[Jon Skeet [C# MVP]]

StreamReader and File.OpenText sort of worked. They gave me the last line
in the text file.

Then I suspect you're using them incorrectly. Perhaps you're calling
ReadLine multiple times, and only using the last returned value?

 

[J.S.]

Use File.OpenText, or new StreamReader to create a TextReader which
reads data from a file. After that, use TextReader.ReadToEnd to read
the whole file.

Thanks, Jon! That worked fine.

J.S.

 

[J.S.]

Then I suspect you're using them incorrectly. Perhaps you're calling

ReadLine multiple times, and only using the last returned value?

You were right, Jon. I was using the wrong code first.

I changed this:

StreamReader re = File.OpenText("D:\\My Documents\\Visual Studio
2005\\textfile.txt");
string input = null;
while ((input = re.ReadLine()) != null)
{
textBox1.Text = input;
}

to this:

// Read the file as one string.
System.IO.StreamReader myFile =
new System.IO.StreamReader("D:\\My Documents\\Visual Studio
2005\\textfile.txt");
string myString = myFile.ReadToEnd();
myFile.Close();
textBox1.Text = myString;

and it worked as desired.

Thanks,
J.S.

 

[J.S.]

When I try to debug this code I get this error message:

An object reference is required for the nonstatic field, method, or property
'System.Windows.Forms.Control.Controls.get'

My code is:

StreamReader myFile = new StreamReader("D:\\My Documents\\Visual Studio
2005\\textfile.txt");
string myString = myFile.ReadToEnd();
string replacedString = textBox2.Text;

foreach (object o in Form1.Controls)
{
if (o is TextBox)
{
myString.Replace("@@" + ((TextBox)o).Name + "@@", ((TextBox)o).Text);
}
}
myFile.Close();
// Display the file contents.
textBox1.Text = myString;

I already have the "using System.Windows.Forms;" directive in my cs file.

 

[Jon Skeet [C# MVP]]

When I try to debug this code I get this error message:

An object reference is required for the nonstatic field, method, or property
'System.Windows.Forms.Control.Controls.get'

My code is:

StreamReader myFile = new StreamReader("D:\\My Documents\\Visual Studio
2005\\textfile.txt");
string myString = myFile.ReadToEnd();
string replacedString = textBox2.Text;

foreach (object o in Form1.Controls)
{
if (o is TextBox)
{
myString.Replace("@@" + ((TextBox)o).Name + "@@", ((TextBox)o).Text);
}
}
myFile.Close();
// Display the file contents.
textBox1.Text = myString;

I already have the "using System.Windows.Forms;" directive in my cs file.

Form1 is the name of a class, not an instance. When you say:

foreach (object o in Form1.Controls)

which *instance* of Form1 are you talking about? Solve that and I think
you'll find the answer...

 

[J.S.]

Form1 is the name of a class, not an instance. When you say:

foreach (object o in Form1.Controls)

which *instance* of Form1 are you talking about? Solve that and I think
you'll find the answer...

I have only one Form1 in my application but you are probably referring to
something else.

J.S.

 

[Jon Skeet [C# MVP]]

I have only one Form1 in my application but you are probably referring to
something else.

No, I'm saying that Form1 is a class. You *may* have only created one
instance, but how's the compiler going to know that? Put it this way -
using Form1.Controls is like using String.Length - what would you
expect a call to String.Length to return?

You need to use the Controls property on a reference to an instance to
Form1, not on the type itself.

 

[J.S.]

No, I'm saying that Form1 is a class. You *may* have only created one

instance, but how's the compiler going to know that? Put it this way -
using Form1.Controls is like using String.Length - what would you
expect a call to String.Length to return?

You need to use the Controls property on a reference to an instance to
Form1, not on the type itself.

Ok! I changed Form1.Controls to this.Controls and it worked.

Thanks, Brendan and Jon!

J.S.

 

[J.S.]

Ok! I changed Form1.Controls to this.Controls and it worked.

Sorry, I was looking at something else. Just ignore that.

 

[J.S.]

Ok! I changed Form1.Controls to this.Controls and it worked.

Actually, I really did get it working.

 

[J.S.]

Thanks to Jon Skeet and Brendan Green for their help.

Here is the code I eventually used for the application (in case anyone else
is interested):

foreach (Control Ctl in this.Controls)
{
if (Ctl.GetType() == typeof(TextBox))
{
TextBox Txt = (TextBox)Ctl;
myString = myString.Replace("@@" + Txt.Name + "@@", Txt.Text);
}
}

--

 

[Jon Skeet [C# MVP]]

Thanks to Jon Skeet and Brendan Green for their help.

Here is the code I eventually used for the application (in case anyone else
is interested):

foreach (Control Ctl in this.Controls)
{
if (Ctl.GetType() == typeof(TextBox))
{
TextBox Txt = (TextBox)Ctl;
myString = myString.Replace("@@" + Txt.Name + "@@", Txt.Text);
}
}

There's no need to use typeof here. Just use:

foreach (Control control in Controls)
{
TextBox textBox = control as TextBox;
if (textBox != null)
{
myString = myString.Replace("@@"+textBox.Name+"@@",
textBox.Text);
}
}

That's more idiomatic C#, IMO.

 

[J.S.]

Thanks, Jon!