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    <p>If the exception being thrown while converting (assigning value) (i.e. when <a href="http://msdn.microsoft.com/en-us/library/zb260h9b.aspx" rel="nofollow">TypeConverter.ConvertFrom()</a> is called) to a property in the property grid (for example, InvalidCastException), then you can catch in the <a href="http://msdn.microsoft.com/en-us/library/system.componentmodel.typeconverter.aspx" rel="nofollow">TypeConverter</a> for that property.</p> <pre><code>class MyTypeConverter : TypeConverter { public override bool ConvertFrom(ITypeDescriptorContext context, Type sourceType) { try { return base.ConvertFrom(context, sourceType); } catch(Exception e) { // Process the exception (for example, Log(e)) or Debug.Assert() throw; } } } // Using the TypeConverter in your class class MyClass { [ReadOnly(false)] [PropertyOrder(1)] [DisplayName("Property 1")] [TypeConverter(typeof(MyTypeConverter))] public int Property1 { get; set; } } </code></pre> <p>You can also override other methods of the base <a href="http://msdn.microsoft.com/en-us/library/system.componentmodel.typeconverter.aspx" rel="nofollow">TypeConverter</a> class accordingly.</p> <p>Going by the example, that you have added, it looks like you want the to deduce the reason why the communication with the device has failed (port not open, etc.). Then why not set a property or flag (for example, <code>Error</code> or <code>CommunicationError</code>) in the <code>Device</code> class that tells whether the specific error has occurred.</p> <p>Then in the <code>TypeConverter</code> check for this property before accessing other properties, if in error then simply return from the <code>ConvertFrom()</code> without calling the <code>base</code> implementation. If the error is recoverable, which in your case appears to be a communication error, then allow the user to retry, rather than throwing an exception.</p> <p>In addition, if you are mapping the device parameters directly onto the class and you have a property that you use in the property grid but do not want it to be written on the device, then mark it with a custom attribute (say boolean <code>DeviceWritable</code>). In the communication layer (where you actually write the values to the device), check for this custom attribute, if it is set as <code>true</code> then write to the device otherwise do not write to the device. </p>
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    1. POHow to handle the exceptions that thrown by a propertygrid?
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    1. USDevendra D. Chavan
    1. USDevendra D. Chavan
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    1. POHow to handle the exceptions that thrown by a propertygrid?
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    1. COThanks a lot for help! I think it will rescue me from all these problems that i have with additional comboboxes, textfields e.c. ;) but i still have to find a way to get rid of these exceptions that came directly from my device.
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    2. COI have updated the answer to reflect the example given though I not sure why the `device` is throwing an exception! In case of error, you should have an error flag(s) or register(s) on the device that indicate error and its type.
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      1. USDevendra D. Chavan
    3. COThe reason that device throwing an exception is mostly a malfunction of communication. So if the bytes that i read are unexpected, then either my machine is not on or it is running slow or my RS232 cable is burned up, e.c... So in some errors, i'm sure that even the DeviceWritable method won't work. I think i have the register that you mentioned. For all expectable (forseen) errors, i have a method to read errors from the device. But for unexpectable (really stupid and buggy) ones, i must throw these exceptions i guess.
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