Develop Reference

Disable C# Form until external Excel application is closed

I have a button on a C# Windows forms application that runs the code below:
private void btnAddDataToCSV_Click(object sender, EventArgs e)
{
string path = "D:\MyCsvFile.csv";
Process.Start(path);
}
Basically, the user needs to be able to make changes to a CSV file. The user is most comfortable making these changes in Microsoft Excel. I found the above code online from someone who has many years of experience working with MS Office products and C#. This guy explained that the code below works but is more error prone than using "Process.Start()" as shown above.
string path = "D:\MyCsvFile.csv";
var ExcelApp = new Excel.Application();
ExcelApp.Workbooks.OpenText(path, Comma: true);
ExcelApp.Visible = true;
This guy explains that "Process.Start()" works because Windows is set up to use Excel as the default program for opening CSV files.
Anyways, when the user clicks the button above (btnAddDataToCSV), I need my C# form to become disabled (all the buttons grayed out) until the user closes the Excel workbook that is displaying the CSV file. Potentially, I may need the C# program to read the CSV file immediately after the user closes Excel.
Ho do I do this?
I assume... I need to do something like... "disable C# form... then Wait for Excel close event... then once excel close event happens... enable C# form and read CSV file."
Below is the code I have for reading the CSV file:
string path = "D:\MyCsvFile.csv";
var reader = new StreamReader(File.OpenRead(path));
List<string> listA = new List<string>();
List<string> listB = new List<string>();
List<string> listC = new List<string>();
while (!reader.EndOfStream)
{
var line = reader.ReadLine();
var values = line.Split(',');
listA.Add(values[0]);
listB.Add(values[1]);
listC.Add(values[2]);
}

I think that you need to use an event handler for process that exits.
Something like this:
private void btnAddDataToCSV_Click(object sender, EventArgs e)
{
//disable form
string path = "D:\MyCsvFile.csv";
using (myProcess = new Process())
{
myProcess.EnableRaisingEvents = true;
myProcess.Exited += new EventHandler(Excel_Exit);
myProcess.Start(path);
}
}
public void Excel_Exit(object sender, System.EventArgs e){
//enableForm
}
Process.Exited example in documentation: https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.process.exited?view=netcore-3.1

I was unable to get the solution above to work even though the solution is similar to Microsoft's solution.
https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.process.exited?view=netcore-3.1
I found this:
Why is my process's Exited method not being called?
It says:
"I've come across examples that place new Process() in a using clause. Do not do that if you want to use the Exited feature. The using clause destroys the instance along with any event handles on Exited."
It says:
using(var process = new Process())
Should be:
var process = new Process();
This makes no since because the link above that I provided for Microsoft is an example of how to use the "Process.Exited Event" and it uses "using(var process = new Process())"
But sure enough... for some reason when I tried "var process = new Process();" it worked... This is the code that worked:
private void btnAddDataToCSV_Click(object sender, EventArgs e)
{
var myProcess = new Process();
myProcess.EnableRaisingEvents = true;
myProcess.Exited += new EventHandler(Excel_Exit);
myProcess.StartInfo.FileName = "D:\\MyCsvFile.csv";
myProcess.Start();
}
public void Excel_Exit(object sender, System.EventArgs e)
{
MessageBox.Show("Success!!");
}
Here is the code that does not work... But I don't understand why because it is similar to Microsoft's example.
private Process myProcess;
private void btnAddDataToCSV_Click(object sender, EventArgs e)
{
using (myProcess = new Process())
{
myProcess.EnableRaisingEvents = true;
myProcess.Exited += new EventHandler(Excel_Exit);
myProcess.StartInfo.FileName = "D:\\MyCsvFile.csv";
myProcess.Start();
}
}
public void Excel_Exit(object sender, System.EventArgs e)
{
MessageBox.Show("Success!!");
}
When you close excel... the event never fires... Can someone explain this? Surely Microsoft's example isn't wrong.

c# Updating Text Box with Powershell Console details in real time

So I'm new to C#. I had been building all my tools (7 years worth of tools) in Powershell as I could never obtain a Visual Studio License but now that I have it...
I've been reading about system.componentmodel.backgroundworker however I'm having trouble implementing it.
Heres my code without Background worker and with. Can someone help me in seeing how I can implement it so my UI Doesn't go unresponsive when I kick off the Powershell jobs and I can actually get (somewhat) real updates in the text box
using System;
using System.Text;
using System.Windows.Forms;
using System.Collections.ObjectModel;
using System.Management.Automation;
using System.Management.Automation.Runspaces;
using System.IO;
namespace ServerStatusChecks
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
// run our script and put the result into our textbox
// NOTE: make sure to change the path to the correct location of your script
textBox1.Text = RunScript(LoadScript(#"c:\utils\Script.ps1"));
}
// helper method that takes your script path, loads up the script
// into a variable, and passes the variable to the RunScript method
// that will then execute the contents
private string LoadScript(string filename)
{
try
{
// Create an instance of StreamReader to read from our file.
// The using statement also closes the StreamReader.
using (StreamReader sr = new StreamReader(filename))
{
// use a string builder to get all our lines from the file
StringBuilder fileContents = new StringBuilder();
// string to hold the current line
string curLine;
// loop through our file and read each line into our
// stringbuilder as we go along
while ((curLine = sr.ReadLine()) != null)
{
// read each line and MAKE SURE YOU ADD BACK THE
// LINEFEED THAT IT THE ReadLine() METHOD STRIPS OFF
fileContents.Append(curLine + "\n");
}
// call RunScript and pass in our file contents
// converted to a string
return fileContents.ToString();
}
}
catch (Exception e)
{
// Let the user know what went wrong.
string errorText = "The file could not be read:";
errorText += e.Message + "\n";
return errorText;
}
}
// Takes script text as input and runs it, then converts
// the results to a string to return to the user
private string RunScript(string scriptText)
{
// create Powershell runspace
Runspace runspace = RunspaceFactory.CreateRunspace();
// open it
runspace.Open();
// create a pipeline and feed it the script text
Pipeline pipeline = runspace.CreatePipeline();
pipeline.Commands.AddScript(scriptText);
// add an extra command to transform the script output objects into nicely formatted strings
// remove this line to get the actual objects that the script returns. For example, the script
// "Get-Process" returns a collection of System.Diagnostics.Process instances.
pipeline.Commands.Add("Out-String");
// execute the script
Collection<PSObject> results = pipeline.Invoke();
// close the runspace
pipeline.Dispose();
runspace.Close();
// convert the script result into a single string
StringBuilder stringBuilder = new StringBuilder();
foreach (PSObject obj in results)
{
stringBuilder.AppendLine(obj.ToString());
}
// return the results of the script that has
// now been converted to text
return stringBuilder.ToString();
}
private void Form1_Load(object sender, EventArgs e)
{
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
}
}
}
Now here's the code with me trying to implement BW (It's a bit of a monster as I've tried to get it to work several ways and it's a mess now)
using System;
using System.Text;
using System.Windows.Forms;
using System.Collections.ObjectModel;
using System.Management.Automation;
using System.Management.Automation.Runspaces;
using System.ComponentModel;
using System.Threading;
using System.IO;
namespace ServerStatusChecks
{
public partial class Form1 : Form
{
private BackgroundWorker bw = new BackgroundWorker();
public Form1()
{
InitializeComponent();
bw.WorkerReportsProgress = true;
bw.WorkerSupportsCancellation = true;
bw.DoWork += new DoWorkEventHandler(bw_DoWork);
}
private string LoadScript(string filename)
{
try
{
// Create an instance of StreamReader to read from our file.
// The using statement also closes the StreamReader.
using (StreamReader sr = new StreamReader(filename))
{
// use a string builder to get all our lines from the file
StringBuilder fileContents = new StringBuilder();
// string to hold the current line
string curLine;
// loop through our file and read each line into our
// stringbuilder as we go along
while ((curLine = sr.ReadLine()) != null)
{
// read each line and MAKE SURE YOU ADD BACK THE
// LINEFEED THAT IT THE ReadLine() METHOD STRIPS OFF
fileContents.Append(curLine + "\n");
}
// call RunScript and pass in our file contents
// converted to a string
return fileContents.ToString();
}
}
catch (Exception e)
{
// Let the user know what went wrong.
string errorText = "The file could not be read:";
errorText += e.Message + "\n";
return errorText;
}
}
private void button1_Click(object sender, EventArgs e)
{
if (bw.IsBusy != true)
{
bw.RunWorkerAsync();
}
// run our script and put the result into our textbox
// NOTE: make sure to change the path to the correct location of your script
textBox1.Text = RunScript(LoadScript(#"c:\utils\Script.ps1"));
}
private void bw_DoWork(object sender, EventArgs e)
{
}
// Takes script text as input and runs it, then converts
// the results to a string to return to the user
private string RunScript(string scriptText)
{
// create Powershell runspace
Runspace runspace = RunspaceFactory.CreateRunspace();
// open it
runspace.Open();
// create a pipeline and feed it the script text
Pipeline pipeline = runspace.CreatePipeline();
pipeline.Commands.AddScript(scriptText);
// add an extra command to transform the script output objects into nicely formatted strings
// remove this line to get the actual objects that the script returns. For example, the script
// "Get-Process" returns a collection of System.Diagnostics.Process instances.
pipeline.Commands.Add("Out-String");
// execute the script
Collection<PSObject> results = pipeline.Invoke();
// close the runspace
pipeline.Dispose();
runspace.Close();
// convert the script result into a single string
StringBuilder stringBuilder = new StringBuilder();
foreach (PSObject obj in results)
{
stringBuilder.AppendLine(obj.ToString());
}
// return the results of the script that has
// now been converted to text
return stringBuilder.ToString();
}
// helper method that takes your script path, loads up the script
// into a variable, and passes the variable to the RunScript method
// that will then execute the contents
private void Form1_Load(object sender, EventArgs e)
{
Thread.Sleep(1000);
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
Thread.Sleep(1000);
}
}
}

The problem is that you're not running anything in the bw_DoWork event, which is where the actual background work is run. You should change this section of your code to the following:
private void button1_Click(object sender, EventArgs e)
{
if (bw.IsBusy != true)
{
bw.RunWorkerAsync();
}
}
private void bw_DoWork(object sender, EventArgs e)
{
// run our script and put the result into our textbox
// NOTE: make sure to change the path to the correct location of your script
textBox1.Text = RunScript(LoadScript(#"c:\utils\Script.ps1"));
}
The reason this works is that the bw_DoWork method is an event listener, which means it "listens" for when the RunWorkerAsync() method is called, which you do when the button is clicked. bw_DoWork knows to listen for the RunWorkerAsync() function is because the line you put at the top of the program:
bw.DoWork += new DoWorkEventHandler(bw_DoWork);
This basically tells DoWork to sit and wait for the event to fire off. This is commonly referred to as "subscribing to the event". When it does, a new thread spawns that does whatever is in bw's DoWork event while your original thread, which contains the UI (and is commonly refered to as the 'UI Thread') keeps on trucking. Events and Asynchronous threads are a tricky subject to wrap your head around, but once you do it's a fantastic piece of .NET.
EDIT:
Alright, so the above is correct as far as getting bw to run properly, but it causes this error:
Error: {"Cross-thread operation not valid: Control 'textBox1' accessed from a thread other than the thread it was created on."}
Above I said that the main thread is called the "UI Thread". This also means that the UI is locked to that thread. Therefore, your BackgroundWorker cannot touch the UI elements. Therefore the offending line is textBox1.Text = RunScript(LoadScript(#"c:\utils\Script.ps1"));
The easiest way to fix this is to have RunScript() pass its value to a public variable, then assign the variable after bw has done its processing. We do this by subscribing to another built-in event in BackgroundWorker called RunWorkerCompleted.
First, declare a new static string at the top of the class:
static string RunScriptResult;
Then, add a new listener to bw by modifying Form1:
public Form1()
{
//...
bw.DoWork += new DoWorkEventHandler(bw_DoWork);
bw.RunWorkerCompleted += new bw_RunWorkerCompleted; //new listener event
}
Next, change bw_DoWork to assign the output to the string we created earlier:
private void bw_DoWork(object sender, EventArgs e)
{
RunScriptResult = RunScript(LoadScript(#"c:\utils\Script.ps1"));
}
Next, add a new event handler method for RunWorkerCompleted:
private void bw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
textBox1.Text = RunScriptResult;
}
The above event does not fire until bw is finished, and it runs in the UI thread. These modifications should get you where you need to be.

Iperf3 C# Automation Issue

I am trying to automate iperf3 using c#. The problem is that for some reason the iperf3 output is redirected once the iperf test is done and does not redirect it in real time.
public void RunIperf()
{
{
sortOutput = new StringBuilder();
this.dummyProcess .OutputDataReceived += CaptureOutput;
this.dummyProcess .ErrorDataReceived += CaptureError;
this.dummyProcess .Start();
this.dummyProcess .BeginOutputReadLine();
this.dummyProcess .BeginErrorReadLine();
this.dummyProcess .WaitForExit();
}
static void CaptureOutput(object sender, DataReceivedEventArgs e)
{
ShowOutput(e.Data, ConsoleColor.Green);
}
}
This code works for iperf2 wherein I get data on my console in real time but not for iperf3. I am not sure what the issue is.

Try using the --forceflush flag to iperf3.

Check if the form is loaded

I have two forms.
One of them is the main form (let's call it MainForm)
the other one is for showing some warning (let's call it dialogForm)
. dialogForm has a label in it. When i click a button in MainForm, dialogForm opens.
But label in dialogForm is blank. It doesn't have time to load actually. I want to check if the dialogForm fully loaded then proccess can continue in MainForm.
For example:
dialogForm tempFrm = new dialogForm();
tempFrm.Show(); // I want to wait till the dialogForm is fully loaded. Then continue to "while" loop.
while(..)
{
...
}

Why not create a boolean value, and a method to access it..
private bool Ready = false;
public ConstructorMethod()
{
// Constructor code etc.
Ready = true;
}
public bool isReady()
{
return Ready;
}

you can try the following
private bool Is_Form_Loaded_Already(string FormName)
{
foreach (Form form_loaded in Application.OpenForms)
{
if (form_loaded.Text.IndexOf(FormName) >= 0)
{
return true;
}
}
return false;
}
you can also look in this
Notification when my form is fully loaded in C# (.Net Compact Framework)?

So you need to consume the forms Shown event:
tempFrm.Shown += (s, e) =>
{
while(..)
{
}
}
But you're going to have another problem. It's going to block the thread. You need to run this while loop on another thread by leveraging a BackgroundWorker or Thread.

Your while(...) blocks the UI thread so child form will never got messages and will not be loaded.
To achive you goal you should subscribe to the Load event and continue your code in the handler.
void Click()
{
var tempFrm = new dialogForm();
tempFrm.Load += frmLoad;
tempFrm.Show();
}
void frmLoad(object s, EventArgs ea)
{
// form loaded continue your code here!
}

You can use Form.IsActive property.
Or just;
public bool IsFormLoaded;
public MyForm()
{
InitializeComponent();
Load += new System.EventHandler(FormLoaded);
}
private void FormLoaded(object sender, EventArgs e)
{
IsFormLoaded = true;
}
and check if YourForm.IsFormLoaded, true or false

How to use AxWebBrowser in console application

I wanna use AxWebBrowser on console application, but it give me following exception:
Exception of type 'System.Windows.Forms.AxHost+InvalidActiveXStateException' was thrown.
anybody please help me on this by any sample code for using AxWebBrowser in console application c# without any exeption ...

Yes, the [STAThread] attribute is required on your Main() method so that COM is initialized properly to make the main thread a Single Threaded Apartment. That's not all though, you will also need to pump a message loop. That's a requirement for an STA. Without one, WebBrowser cannot update its state or run its event handlers, you'll never get the DocumentCompleted event for example. You can get a message loop with Application.Run().
Your console application is now indistinguishable from a Windows Forms application. It is actually easier to get everything right by starting a new project with the Windows Forms application project template, then Project + Properties, Output type = Console Application. Edit the Application.Run() call in Program.cs so it doesn't create a form. It won't make dealing with Application.Run() any easier, consider a Timer to run code.

Add the STAThread attribute to your Main method.
However, you should not be using the "raw" ActiveX control.
Instead, add a reference to System.Windows.Forms.dll and use the WebBrowser class. (Yes, you can do that in a Console app)
Also, automating IE is not ideal. You should consider using the WebCLient class.

My class is as below but in the run time it gives me System.Windows.Forms.AxHost+InvalidActiveXStateException:
public class Browse
{
private static AxWebBrowser wBrowser;
public static Result StartBrowse(string url)
{
var validUri = (url.Contains("http://") ? url : "http://" + url);
wBrowser = new AxWebBrowser();
System.Resources.ResourceManager resources = new System.Resources.ResourceManager(typeof(AxWebBrowser));
((ISupportInitialize) (wBrowser)).BeginInit();
wBrowser.OcxState = ((AxHost.State)(resources.GetObject("wBrowser.OcxState")));
wBrowser.NewWindow2 += wBrowser_NewWindow2;
wBrowser.NewWindow3 += wBrowser_NewWindow3;
wBrowser.DocumentComplete += wBrowser_DocumentComplete;
wBrowser.DownloadComplete += wBrowser_DownloadComplete;
if (string.IsNullOrEmpty(html) || validUri != url)
{
object empty = System.Reflection.Missing.Value;
wBrowser.Silent = true;
wBrowser.Navigate(validUri, ref empty, ref empty, ref empty, ref empty);
}
return null;
}
static void wBrowser_DownloadComplete(object sender, EventArgs e)
{
doAlgorithm();
}
static void wBrowser_DocumentComplete(object sender, DWebBrowserEvents2_DocumentCompleteEvent e)
{
doAlgorithm();
}
static void wBrowser_NewWindow3(object sender, DWebBrowserEvents2_NewWindow3Event e)
{
e.cancel = true;
}
static void wBrowser_NewWindow2(object sender, DWebBrowserEvents2_NewWindow2Event e)
{
e.cancel = true;
}
}

First, the thread in which the control is hosted must be in single-threaded apartment, you can either put the STAThread in your Main method, or create a separated Thread like this:
var thread = new Thread(() =>
{
//My code
});
thread.SetApartmentState(ApartmentState.STA);
thread.Start();
thread.Join(); //Wait for thread termination
Second, you must start a message loop:
while (true) //Put some exit condition
System.Windows.Forms.Application.DoEvents();
Third the control must be hosted in a visible form. The form must be visible just once, so to avoid "flickering", you can write this code:
var browser = new AxWebBrowser();
var hostForm = new Form();
//Set form 0 size, without any control box / title / icon
hostForm.Width = 0;
hostForm.Height = 0;
hostForm.ShowInTaskbar = false;
hostForm.ControlBox = false;
hostForm.ShowIcon = false;
hostForm.MinimizeBox = false;
hostForm.MaximizeBox = false;
//Add browser control
hostForm.Controls.Add(browser);
//Show and immediately hide
hostForm.Show();
hostForm.Hide();
Finally you might want to disable the "click" sound (How to disable click sound in WebBrowser Control)
The final code:
class Program
{
[STAThread]
static void Main(string[] args)
{
URLSecurityZoneAPI.InternetSetFeatureEnabled(URLSecurityZoneAPI.InternetFeaturelist.DISABLE_NAVIGATION_SOUNDS, URLSecurityZoneAPI.SetFeatureOn.PROCESS, true);
var browser = new AxWebBrowser();
var hostForm = new Form();
hostForm.Width = 0;
hostForm.Height = 0;
hostForm.ShowInTaskbar = false;
hostForm.ControlBox = false;
hostForm.ShowIcon = false;
hostForm.MinimizeBox = false;
hostForm.MaximizeBox = false;
hostForm.Controls.Add(browser);
hostForm.Show();
hostForm.Hide();
browser.DocumentComplete += delegate(object sender, DWebBrowserEvents2_DocumentCompleteEvent e)
{
var doc = (IHTMLDocument3)browser.Document;
Console.WriteLine(doc.documentElement.innerHTML);
};
browser.Navigate("www.google.com");
while (true)
System.Windows.Forms.Application.DoEvents();
}
}