LINQ to xml query - C# Discussion Boards

Hi,

I am designing simple Calculator. And TextBox contains "300+500-10" values.
Kindly let me know, how may I calculate it from TextBox ? or Let me know another method.

Thank you
(Riaz)

Follow the link below:
http://www.codeproject.com/KB/recipes/MathieuMathParser.aspx?artkw=evaluate expression

Hope this will help.

Anurag Gandhi.
http://www.gandhisoft.com
Life is a computer program and every one is the programmer of his own life.
My latest article: Group GridView Data

Thanks for Helping friend

If you look above the text box when you enter a reply, there are two "link" widgets.
If you highlight your link, and press one of the widgets, it converts the link to a clickable link: easier for people to use, and looks better!

Your original:

http://www.codeproject.com/KB/recipes/MathieuMathParser.aspx

First "link"
An extensible math expression parser with plug-ins

Second "link[^]" (It gives a "new window/tab" option to the link)
An extensible math expression parser with plug-ins[^]

Much prettier!

Real men don't use instructions. They are only the manufacturers opinion on how to put the thing together.

Digital man: "You are, in short, an idiot with the IQ of an ant and the intellectual capacity of a hose pipe."

Thanks for pointing it out.
Will use it next time. Smile | :)

Anurag Gandhi.
http://www.gandhisoft.com
Life is a computer program and every one is the programmer of his own life.
My latest article: Group GridView Data

Welcome!

Real men don't use instructions. They are only the manufacturers opinion on how to put the thing together.

Digital man: "You are, in short, an idiot with the IQ of an ant and the intellectual capacity of a hose pipe."

Very good link buddy..

Hi,
I am trying to delete some nodes from an xml document. I am using LINQ to xml and want to stick to this approach. Here is my XML document:

<?xml version="1.0" encoding="utf-8"?>
<Project>
  <Clips>
    <Clip ID="1" Sequence="1">
      <Name></Name>
      <Description></Description>
      <Location></Location>
      <Duration></Duration>
      <Images>
        <Image ID="1">
          <Name></Name>
          <Description></Description>
          <Location></Location>
          <StartTime></StartTime>
          <EndTime></EndTime>
        </Image>
      </Images>
    </Clip>
    <Clip ID="2" Sequence="1">
      <Name>Bazingaaa</Name>
      <Description>Masdljaslda</Description>
      <Location>C:\Videos</Location>
      <Duration>00:00:30</Duration>
      <Images>
        <Image ID="1">
          <Name>Faheem</Name>
          <Description>MyImage</Description>
          <Location>C:\Images</Location>
          <StartTime>00:00:00</StartTime>
          <EndTime>00:00:10</EndTime>
        </Image>
        <Image ID="2">
          <Name>Fawaz</Name>
          <Description>MyImage</Description>
          <Location>C:\Images</Location>
          <StartTime>00:00:00</StartTime>
          <EndTime>00:00:10</EndTime>
        </Image>
      </Images>
    </Clip>
  </Clips>
</Project>

I have to perform two cases. 1. Delete clip node based on ID. 2. Clear whole project root tag.
I am using the following code to delete nodes.

// Obtain the first clip entry
                            IEnumerable<XElement> clip = (from c in this.oProjectDoc.Element("Project").Element("Clips").Elements("Clip")
                                   where c.Attribute("ID").Value.Equals(ID)
                                   select c);
                            
                            // Delete clip entry
                            foreach (XElement xe in clip)
                                xe.Remove();

                            // Save updated options document to file system
                            this.oProjectDoc.Save(this.oProjectPath.FullName);

Have tried this as well.

var q = from node in oProjectDoc.Root.DescendantsAndSelf("Clips")
        let attr = node.Attribute("ID")
        where attr != null && attr.Value == clipId
        select node;
q.ToList().ForEach(x => x.Remove());
oProjectDoc.Save(this.oProjectPath.FullName);

Problem happens when i try to delete the last clip node or the clear the whole root "Project" tag. I get a lingering end node tag. Like:

</Clip>

Any solutions to that. Kindly please also tell me how can clear all my nodes from xml document. i.e. totally empty my xml document and start afresh without deleting the xml file.

Thanks in advance

Regards...
Smile | :)

Instead of this:

C#

var q = from node in oProjectDoc.Root.DescendantsAndSelf("Clips")
        let attr = node.Attribute("ID")
        where attr != null && attr.Value == clipId
        select node;
q.ToList().ForEach(x => x.Remove());

Why can't you do this:

C#

var q = (from node in oProjectDoc.Root.DescendantsAndSelf("Clips")
        let attr = node.Attribute("ID")
        where attr != null && attr.Value != clipId
        select node);
oProjectDoc.Root.RemoveAll();
foreach(XElement element in q)
{
    oProjectDoc.Root.Add(element);
}

".45 ACP - because shooting twice is just silly" - JSOP, 2010
-----
You can never have too much ammo - unless you're swimming, or on fire. - JSOP, 2010
-----
"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass." - Dale Earnhardt, 1997

Hi,

will u tell me, how can i display an warning message to the user if the file he/she is uploading is open in his machine..

In my Application, i can upload only a file of type *.txt or *.csv,

so could u tell me how can i display a message to the user, when he is uploading a file of (.txt or .csv)type only when that particular file is open in his machine..

As of now in my application, it makes the application crash if that uploading file is open in user machine..

please check my code here..

private void BtnBrowseClick(object sender, RoutedEventArgs e)
        {
            OpenFileDialog file1 = new OpenFileDialog { Multiselect = false, Filter = "All Supported Files |*.txt;*.csv|Text|*.txt|CSV |*.csv"};
            if (file1.ShowDialog() == true)
            {
                new FileInfo(file1.FileName);
                try
                {
                    using (Stream str = file1.OpenFile())
                    {
                        TextReader reader = new StreamReader(str);
                        reader.ReadToEnd();
                        txtFileName.Text = file1.FileName;
                        txtFileName.IsEnabled = false;

                    }
                }
                catch
                {
                    txtFileName.Text = file1.FileName;
                    txtFileName.IsEnabled = false;
                    MessageBox.Show("Please check the file has been Closed before you upload", "Manual File Upload");
                }
            }
        }

It is showing warning message if i change the permission of that file(.txt or .csv) or if i dint changed the permission, it is not showing any warning message, could u tell me how can i do it in a right way..

If possible tell me with a sample code, so i change my code or alter it...

Thanks

There is a hack using a Try Catch Block and catching an IOException . In your case you could do something like this,

private void BtnBrowse_Click(object sender, RoutedEventArgs e)
        {
            OpenFileDialog file1 = new OpenFileDialog { Multiselect = false, Filter = "All Supported Files |*.txt;*.csv|Text|*.txt|CSV |*.csv" };
            if (file1.ShowDialog() == true) 
            {
                new FileInfo(file1.FileName); 
                using (Stream str = file1.OpenFile())
                {
                    try
                    {
                        System.IO.FileStream fs = System.IO.File.OpenWrite(file1.FileName);
                        fs.Close();
                    }
                    catch (IOException)
                    {
                        MessageBox.Show("Please check the file has been Closed before you upload", "Manual File Upload");
                        return;
                    }
                    TextReader reader = new StreamReader(str); 
                    reader.ReadToEnd();
                    textBox1.Text = file1.FileName;
                    textBox1.IsEnabled = false; 
                } 
            }
        }

This solution is not very elegant but it works Big Grin | :-D

.The only other way I know would be to use the proper Win32 API's, which is tiresome.

Happy Coding

I used the above code in my application,

In both the condition like if the uploading file is open and close it is executing the catch statement,
try block is not executing if the uploading file is closed in user machine...

and also the code below the catch block is not executing...

only catch block is executing in this case,

So can u tell me how can i alter it to make it run successfully...

Sorry for that, but in your case this won't work as the OpenFileDialog Locks the file itself, so the IOException will always be caught. I created a function like this

private bool FileInUse(string fileName)
        {            
            try
            {
                System.IO.FileStream fs = System.IO.File.OpenWrite(fileName);
                fs.Close();
                return true;
            }
            catch (IOException ex)
            {
                return false;
            }
        }

and then calling it like this

OpenFileDialog file1 = new OpenFileDialog();            
            if (file1.ShowDialog() == true) 
            {
                if (!FileInUse(file1.FileName))
                {
                    MessageBox.Show("Already Open");
                }
                else
                {
                    using (Stream str = file1.OpenFile())
                    {
                        TextReader reader = new StreamReader(str);
                        reader.ReadToEnd();
                        textBox1.Text = file1.FileName;
                        textBox1.IsEnabled = false;
                    }
                }
            }

but this only works if the file is locked by the application that opens it (such as Word), otherwise if the file is open in an application that doesn't lock the file (such as NotePad), this always returns true.

Hello i have tried to get find some examples that draws behind the desktop icons and the ones i found did not do this in windows 7 atleast. so i thought i would have a go at overriding the onpaint or onrender but since im not the best yet! i can't seem to find the right way to do this. so far i managed to draw a circle behind by following this code

[DllImport("user32.dll")]
static extern IntPtr GetDesktopWindow();

[DllImport("user32.dll")]
static extern IntPtr GetDCEx(IntPtr hwnd, IntPtr hrgn, uint flags);

.......
IntPtr hdc = GetDCEx(GetDesktopWindow(), IntPtr.Zero, 1027);
using(Graphics g = Graphics.FromHdc(hdc))
{
g.FillEllipse(Brushes.Red, 0, 0, 400, 400);
}

then i tought what if i copied the e.graphics and put it into the newly created g and then tried to draw but i can't seem to copy the content of the painteventargs, is it even possible?

so i tought i ask the masters here. anyone know how to do something like this?

Probably impossible. You'd have to subclass the desktop window which I think is not allowed by the OS, then hook its WM_PAINT. That'd mean injecting yourself into explorer.exe (the correct instance). If you were able to accomplish that, it would be GDI/GDI+ only. I don't think you'd be able to render WPF content though.

oh, well i guess i have to find some other solution then. Thanks for the heads up

I have only begun to learn I started with vb but every time I search for an answer most of the results are in c# Is there a tut to un learn vb and convert my knowledge to C# BECAUSE I need relevant search results to learn from Smile | :)

Frazzle the name say's it all

Is shouldn't be too hard to learn C# if you already know VB.NET
The main difference is the syntax and naming conventions. Pretty much everything else is the same.

In the mean time there are some online converters you can use.
C# to VB.NET
VB.NET to C#

Here is a tut which will teach you the basics
After that just use the converters, enter a VB.NET statement and convert to see the C# syntax.

"You get that on the big jobs."

Here you go man

Differences

"Differences Between Microsoft Visual Basic .NET and Microsoft Visual C# .NET" white paper.[^]

Complete Comparison for VB.NET and C#[^]

Comparison of C Sharp and Visual Basic .NET[^]

Code Conversion

Convert VB.NET to C#[^]

Tutorial

C# Tutorial[^]

BTW I have worked in VB 6(4 years ago) & moved to VB.NET but suddenly switched over to C#.NET within a month. So it won't be tough to you too. Cheers

thatraja

My Tip/Tricks
My Dad had a Heart Attack on this day so don't...

I will suggest you to refresh your C and C++ skills. As you know VB.Net, it will not be a big deal to get used to C#.
C# simply uses the syntaxes of C and C++ only.

Hope this helps.
All the best.

The code below works perfect with
removeUser("testuser")
but will not work with
removeUser("domain\test user name")

Does anyone have any idea as to why?

using System;
using System.IO;
using System.Text;
using Microsoft.Win32;
using System.Security;
using System.Threading;
using System.Reflection;
using System.Diagnostics;
using System.Configuration;
using System.Globalization;
using System.ComponentModel;
using System.DirectoryServices;
using System.Security.Principal;
using System.Collections.Generic;
using System.Security.Permissions;
using System.Text.RegularExpressions;
using System.Runtime.InteropServices;
using System.Runtime.Remoting.Contexts;
using System.Runtime.Remoting.Messaging;
using System.Windows.Forms;

namespace AD
{
    class ActiveDirectory
    {

     public static void removeUser(string userName)
        {
            try
            {
                string path = string.Format("WinNT://{0},computer", Environment.MachineName);
                using (DirectoryEntry dirEntry = new DirectoryEntry(path))
                {
                    DirectoryEntry groupEntry = dirEntry.Children.Find("Administrators", "group");
                    if (groupEntry != null)
                    {

                        DirectoryEntry userEntry = dirEntry.Children.Find(userName, "user");
                        groupEntry.Invoke("Remove", new object[] { userEntry.Path.ToString() }); 
                        groupEntry.CommitChanges();
                        userEntry.Dispose();
                    }
                    groupEntry.Dispose();

                    MessageBox.Show("Account Removed Successfully");
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);

            }

        }
    }
}

Local users have a domain prefix?

Anyway, a pretty extensive how-to can be found here http://www.pcreview.co.uk/forums/remove-user-local-group-t3540493.html[^], if you don't mind reading through threads by other folks who've had problems with it.

..and water fell from the sky like rain.

Hi,

Assuming that was the correct link, the remove method is almost 100% identical to the code I posted ... am I missing something?

If you're in the Domain (the machine, I suppose, in the case of the local computer), prepending the Domain apparently doesn't work. Are you getting an exception, or is it just not doing anything?

..and water fell from the sky like rain.

I'm getting an error message

I've gotten a few when trying different things, one is that " the group could not be found (Exception from HRESULT:0x800708AC) " or " The user name could not be found (Exception from HRESULT:0x800708AD ")