Updating StatusStrip text from class

Brad Wick

I have a frmMain which has a StatusStrip on it. Inside my class I have a function which checks for internet connection and when the system is not online, I would like for it to update one of the labels on the StatusStrip. I have tried to do some searching and have tried some examples but can not seem to get it to work. I created the below function in frmMain.cs

public void Set_StatusStrip(string status)
{
    toolStripStatusInternetConnection.Text = "";
}

In inc_functions.cs I have the following function

public void InternetConnectionAvailable()
{
  // code to check for internet connection goes here
  frmMain.Set_StatusStrip("Application Online");
}

The error I get is "An object reference is required for the non-static field, method, or property." Can anyone see what I am doing wrong?

Simon P Stevens

In the "IntererConnectionAvailable" method, you need to be calling Set_StatusStrip on an instance of the form, not on the form class

Object test = new Object();
Object.TestMethod1()           <-- Static Method
test.TestMethod2()             <-- Instance method

You are calling it as if it was a static method, but it's not, it's an instance method. Good luck. (This is a bad design by the way. You shouldn't be using a helper object to set a UI property on the form. Consider reading up about MVC, MVP or other GUI patterns)

Simon

Brad Wick

I have read that it is bad practice, but I have been searching and reading all morning and I can not seem to find anything that is helping me do this the correct way. Can anyone help out with this?

Dirso

You could do something like

public void InternetConnectionAvailable(frmMain f)
{
// code to check for internet connection goes here
f.Set_StatusStrip("Application Online");
}

And when you call InternetConnectionAvailable, you pass an instance of your frmMain.

DaveyM69

This is a perfect situation for using your own custom event. Something like this: Create a delegate and event

public delegate void ConnectionChangedEventHandler(object sender, ConnectionEventArgs e);
public event ConnectionChangedEventHandler ConnectionChanged;

and a ConnectionEventArgs class

public class ConnectionEventArgs
{
public ConnectionEventArgs(bool isConnected)
{
m_IsConnected = isConnected;
}
private bool m_IsConnected;
public bool IsConnected
{
get { return m_IsConnected; }
}
}

then make the InternetConnection call a method

private void InternetConnectionAvailable()
{
OnConnectionChanged(new ConnectionEventArgs(true));
}
protected virtual void OnConnectionChanged(ConnectionEventArgs e)
{
if (ConnectionChanged != null)
ConnectionChanged(this, e);
}

Now you can subscribe to the ConnectionChanged event and update the StatusStrip

MyClassInstance.ConnectionChanged += new MyClass.ConnectionChangedEventHandler(MyClassInstance_ConnectionChanged);
void MyClassInstance_ConnectionChanged(object sender, ConnectionEventArgs e)
{
// Set status strip
}

[edit] This is (obviously) also reusable for when it's not available too

private void InternetConnectionUnavailable()
{
OnConnectionChanged(new ConnectionEventArgs(false));
}

Dave
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)

modified on Thursday, October 16, 2008 1:07 PM

DaveyM69

He's trying to avoid bad/not-recommended practices and this is one of those - why on earth would his Connection class or this particular method in it need to know about the form? It's nothing to do with the connection. Events/delegates are the way to handle this scenario.

Dave
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)