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Winform and ValidateChildren()


Winform and ValidateChildren()

By : Bannu Raka Sivakumar
Date : January 02 2021, 06:48 AM
To fix this issue Is it not abnormal, when you have 20 different rules for 20 controls. Lots of things you can do to DRY this out. If rules are the same for several controls, give those controls the same Validating event handler. If you have just a few rules, you could create your own control class by deriving from the base and bake-in the rule by overriding OnValidating. Or you could override the form's ValidatingChildren method and validate everything in one method.
code :


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WinForms: Cannot get ValidateChildren to raise Validating event of a child control

WinForms: Cannot get ValidateChildren to raise Validating event of a child control


By : syama
Date : March 29 2020, 07:55 AM
like below fixes the issue I think I figured it out. The control was not raising the Validating event because it was not selectable. A Panel control is not by default selectable nor are controls derived from Panel (See link text). So in the UserControl's constructor I called SetStyle(ControlStyles.Selectable, true);. Now it raises the Validating event.
WPF Control Hosted in WinForm Blocks WinForm controls from loaded even with thread

WPF Control Hosted in WinForm Blocks WinForm controls from loaded even with thread


By : Gabriel Mesquita
Date : March 29 2020, 07:55 AM
I wish this helpful for you It looks like from the code you posted that the delay is due to running GetWeather on the UI thread. Assuming that weatherControl is an instance of the WPF control, this runs on the UI thread because that is the thread that its dispatcher belongs to.
If you want to run code on a background thread, one easy way to do so is to use a BackgroundWorker. You could use it something like this:
code :
public void Start()
{
    var worker = new BackgroundWorker();
    worker.DoWork += (sender, args) =>
    {
        GetWeather();
        // put the results of getting the weather in to args.Result
    };
    worker.RunWorkerCompleted += (sender, args) =>
    {
        // use args.Result to update the UI
    };
    worker.RunWorkerAsync();
}
How can I set an errorProvider against ALL invalid form controls when using this.validateChildren()?

How can I set an errorProvider against ALL invalid form controls when using this.validateChildren()?


By : user2873343
Date : March 29 2020, 07:55 AM
I hope this helps . Setting e.Cancel = true is the problem of course. So just don't do that. It is in general a fairly unpleasant feature, making data entry very modal. A much friendlier approach is to give the user free reign of the data entry task, entering data in an order that isn't necessarily the one you envisioned when you set the tab order.
Just write a little helper method that makes it easy. For example:
code :
    private Control firstInvalidControl;

    private void SetValidation(object sender, bool ok, string errMsg) {
        var ctl = (Control)sender;
        if (ok) errorProvider1.SetError(ctl, "");
        else {
            if (firstInvalidControl == null) firstInvalidControl = ctl;
            errorProvider1.SetError(ctl, errMsg);
        }
    }
    private void OKButton_Click(object sender, EventArgs e) {
        firstInvalidControl = null;
        this.ValidateChildren();
        if (firstInvalidControl != null) firstInvalidControl.Focus();
        else {
            // Data is good, use it
            // ...                
        }
    }
Managed DLL referenced by 2 Winform apps. Winform 1 launches Winform 2, but context is shared unless both are executed s

Managed DLL referenced by 2 Winform apps. Winform 1 launches Winform 2, but context is shared unless both are executed s


By : Noor Khan
Date : March 29 2020, 07:55 AM
may help you . The problem was with a global pointer to native data in the C++/CLI DLL. Since the WinForms get their data through several C++/CLI interfaces, it was initially easier to just have them access native data through a global pointer.
code :
NativeLayer::NativeLayerData* native_data;


public ref class Test1Implementer : ITest1
{
     virtual bool TestConnect()
     {
        bool success = native_data->Connect();
        return success;
     }
};

public ref class Test2Implementer : ITest2
{
     virtual bool TestDisconnect()
     {
        bool success = native_data->Disconnect();
        return success;
     }
};
public ref class TestsImplementer : ITests 
{
private:
    NativeLayer::NativeLayerData* native_data;

public:
      TestsImplementer()
      {
         native_data = new NativeLayer::NativeLayerData();
      }

      ref class Test1Implementer : ITest1
      {
         virtual bool TestConnect(TestsImplementer^ tests)
         {
            bool success = tests->native_data->Connect();
            return success;
         }
      };

      ref class Test2Implementer : ITest2
      {
         virtual bool TestDisconnect(TestsImplementer^ tests)
         {
            bool success = tests->native_data->Disconnect();
            return success;
         }
      };
};
Why is ValidateChildren always returning true?

Why is ValidateChildren always returning true?


By : Chris Shultz
Date : March 29 2020, 07:55 AM
fixed the issue. Will look into that further You need to set the Cancel attribute of the CancelEventArgs object being passed to your validation method:
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