How to Add "System default" string in the postion of default audio device in WPF?

Question

How to Add "System default" string in the postion of default audio device in WPF?

MERUN KUMAR MAITY 636

I have a WPF application where I need to show the available audio devices in a ComboBox. I already get the default audio device through my code, But there are two type of audio devices one is Playback (or Speakers) and another is Recording (or Microphone), though I need default audio devices but I need only the default Playback/speaker device.

Now, I want to add "System default" text in the position of default audio Playback/speaker device. To solve this issue we need to add Id where we set sId value for all items in the loop and sIdDefaultRender value for "System default" item at beginning. But I try to add but the default is bool and the Id is string there so much confusion on how I add.

Here is the code -

// Main code
List<AudioDevice> devices = new List<AudioDevice>();

        HRESULT hr = HRESULT.E_FAIL;  
        Guid CLSID_MMDeviceEnumerator = new Guid("{BCDE0395-E52F-467C-8E3D-C4579291692E}");  
        Type MMDeviceEnumeratorType = Type.GetTypeFromCLSID(CLSID_MMDeviceEnumerator, true);  
        object MMDeviceEnumerator = Activator.CreateInstance(MMDeviceEnumeratorType);  
        IMMDeviceEnumerator pMMDeviceEnumerator = (IMMDeviceEnumerator)MMDeviceEnumerator;  


        if (pMMDeviceEnumerator != null)  
        {  
            string sIdDefaultRender = null;  
            string sIdDefaultCapture = null;  
            IMMDevice pDefaultDevice = null;  
            hr = pMMDeviceEnumerator.GetDefaultAudioEndpoint(EDataFlow.eRender, ERole.eConsole, out pDefaultDevice);  
            if (hr == HRESULT.S_OK)  
            {  
                IntPtr hGlobal = Marshal.AllocHGlobal(260);  
                hr = pDefaultDevice.GetId(out hGlobal);  
                sIdDefaultRender = Marshal.PtrToStringUni(hGlobal);  
                Marshal.FreeHGlobal(hGlobal);  
                Marshal.ReleaseComObject(pDefaultDevice);  
            }  
            hr = pMMDeviceEnumerator.GetDefaultAudioEndpoint(EDataFlow.eCapture, ERole.eConsole, out pDefaultDevice);  
            if (hr == HRESULT.S_OK)  
            {  
                IntPtr hGlobal = Marshal.AllocHGlobal(260);  
                hr = pDefaultDevice.GetId(out hGlobal);  
                sIdDefaultCapture = Marshal.PtrToStringUni(hGlobal);  
                Marshal.FreeHGlobal(hGlobal);  
                Marshal.ReleaseComObject(pDefaultDevice);  
            }  

            IMMDeviceCollection pDeviceCollection = null;  
            hr = pMMDeviceEnumerator.EnumAudioEndpoints(EDataFlow.eAll, DEVICE_STATE_ACTIVE | DEVICE_STATE_UNPLUGGED, out pDeviceCollection);  
            if (hr == HRESULT.S_OK)  
            {  
                uint nDevices = 0;  
                hr = pDeviceCollection.GetCount(out nDevices);  

                
                for (uint i = 0; i < nDevices; i++)  
                {  
                    IMMDevice pDevice = null;  
                    hr = pDeviceCollection.Item(i, out pDevice);  
                    if (hr == HRESULT.S_OK)  
                    {  
                        IPropertyStore pPropertyStore = null;  
                        hr = pDevice.OpenPropertyStore(STGM_READ, out pPropertyStore);  
                        if (hr == HRESULT.S_OK)  
                        {  
                            string sFriendlyName = null;  
                            string sDesc = null;  
                            PROPVARIANT pv = new PROPVARIANT();  
                            hr = pPropertyStore.GetValue(ref PKEY_Device_FriendlyName, out pv);  
                            if (hr == HRESULT.S_OK)  
                            {  
                                sFriendlyName = Marshal.PtrToStringUni(pv.pwszVal);  
                            }  
                            hr = pPropertyStore.GetValue(ref PKEY_Device_DeviceDesc, out pv);  
                            if (hr == HRESULT.S_OK)  
                            {  
                                sDesc = Marshal.PtrToStringUni(pv.pwszVal);  
                            }  
                                                       

                            IntPtr hGlobal = Marshal.AllocHGlobal(260);  
                            hr = pDevice.GetId(out hGlobal);  
                            string sId = Marshal.PtrToStringUni(hGlobal);  
                            Marshal.FreeHGlobal(hGlobal);  

                            IMMEndpoint pEndpoint = null;  
                            pEndpoint = (IMMEndpoint)pDevice;  
                            EDataFlow eDirection = EDataFlow.eAll;  
                            hr = pEndpoint.GetDataFlow(out eDirection);  
                            //System.Diagnostics.Trace.WriteLine("\tDirection : " + eDirection.ToString());  
                            string sDirection = "";  
                            if (eDirection == EDataFlow.eRender)  
                                sDirection = "Playback";  
                            else if (eDirection == EDataFlow.eCapture)  
                                sDirection = "Recording";  


                            int nState = 0;  
                            hr = pDevice.GetState(out nState);  
                            if ((nState == DEVICE_STATE_ACTIVE))  
                            {  
                                sFriendlyName += (sId == sIdDefaultRender || sId == sIdDefaultCapture) ? " (System default)" : "";  
                                devices.Add(new AudioDevice() { Name = sFriendlyName, Direction = sDirection, Default = (sId == sIdDefaultRender || (sId == sIdDefaultCapture)) });  
                                //devices.Add(new AudioDevice() { Name = sFriendlyName, Direction = sDirection, Default = (sId == sIdDefaultRender || (sId == sIdDefaultCapture)) });  
                            }  


                            Marshal.ReleaseComObject(pPropertyStore);  
                        }  
                        Marshal.ReleaseComObject(pDevice);  
                    }  
                }  
            }  
            Marshal.ReleaseComObject(pDeviceCollection);  
            ListCollectionView lcv = new ListCollectionView(devices);  
            lcv.GroupDescriptions.Add(new PropertyGroupDescription("Direction"));  
            this.cmb1.ItemsSource = lcv;  


        }  


    }  



    public class AudioDevice  
    {  
        public string Name { get; set; }  
        public string Direction { get; set; }  
        public bool Default { get; set; }  


    }  



}

Here is, how I use in XAML :

<StackPanel>  
            <ComboBox x:Name="cmb1" Width="400">  
                <!--<ComboBox.GroupStyle>  
                    <GroupStyle>  
                        <GroupStyle.HeaderTemplate>  
                            <DataTemplate>  
                                <TextBlock Text="{Binding Name}"/>  
                            </DataTemplate>  
                        </GroupStyle.HeaderTemplate>  
                    </GroupStyle>  
                </ComboBox.GroupStyle>-->  
                <ComboBox.ItemTemplate>  
                    <DataTemplate>  
                        <TextBlock Text="{Binding Name}">  
                            <!--<TextBlock.Style>  
                                <Style TargetType="TextBlock">  
                                    <Setter Property="Background" Value="Transparent"/>  
                                    <Style.Triggers>  
                                        <DataTrigger Binding="{Binding Default}" Value="True">  
                                            <Setter Property="Text" Value="defrt"/>  
                                        <Setter Property="Foreground" Value="Red"/>  
                                          
                                    </DataTrigger>  
                                </Style.Triggers>  
                            </Style>  
                        </TextBlock.Style>-->  
                    </TextBlock>  
                </DataTemplate>  
            </ComboBox.ItemTemplate>  
        </ComboBox>  
    </StackPanel>![237847-audiodevice-list.jpg][1]

I also give an example so, that it can be understand easily.

Just carefully see this image, this is my system scenario. I just take a screenshot of another paid application audio settings which I want to achieve in my WPF application also.

You clearly see the option Speakers (Conexant Smart Audio HD), in my my case this is my Laptop default audio speaker, until I insert any external audio speaker.

If I select this option "Speakers (Conexant Smart Audio HD)", the sound of this speakers are recorded in my paid application. And also there another option name "System default", if I select this "System default" option then still my Speakers (Conexant Smart Audio HD) sound will be recorded because it's my default audio device in this case.

This is the thing I want to achieve.

In this scenario, the Speakers (Conexant Smart Audio HD) disguise as "System default" option and appear in the top of the list, both selection give the same result.

Accepted answer

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Answer 1

Castorix31 90,521

Like in the other thread, add Id in the class :

public class AudioDevice  
{  
    public string Name { get; set; }  
    public string Direction { get; set; }  
    public string Id { get; set; }  
    public bool Default { get; set; }  
}

Then at beginning :

 devices.Add(new AudioDevice()  { Name = "System default", Direction = "Playback", Id = sIdDefaultRender, Default =  true });  
 for (uint i = 0; i < nDevices; i++)  
 // etc...

In the loop :

 devices.Add(new AudioDevice()  { Name = sFriendlyName, Direction = sDirection, Id = sId, Default = (sId == sIdDefaultRender || (sId == sIdDefaultCapture)) });

MERUN KUMAR MAITY 636 Reputation points

2022-09-06T14:30:23.893+00:00
Thank you very much sir, as usual you are here to help me. Your code is really outstanding and it's works perfectly as I want. The "System default" string is successfully appear in the top of that Combo box list. All my requirements are solved.

I am really happy about that, But I have one last request, I wan to test the "System default" that means as you give me the code,

devices.Add(new AudioDevice() { Name = "System default", Direction = "Playback", Id = sIdDefaultRender, Default = true });

in this code the Name = "System default" , my question is, Can I unit test this part, I just want test that it is really the system default device or not.
Instead of the "System default" string I want to get the device name from here, How can I do that?
Castorix31 90,521 Reputation points

2022-09-06T15:33:22.213+00:00

I cannot reply (apparently too many characters)
Reply in link : 109197
MERUN KUMAR MAITY 636 Reputation points

2022-09-09T19:31:52.47+00:00

Thank you very much sir, Sorry for late reply due to my semester exams. I understand each and everything from your code which you given me to test the "System default" string that is really system default or not, your explanation is crystal clear.

Sir, you are so talented because so many people on Stack overflow, Reddit tell me to use the NAudio (open source audio API for .NET) but you give me the solution without using any third part libraries. You just invoke the old win32 API. Your programming skills are so great that you mix C# with win32/C++.

Sometimes I feel, you have the power to write the entire Windows OS by using C++.

But one last question is, How can I add another combo box items in this list? It can be very good if I use XAML. How can I place that combo box item on a specific position like on third item position or before the last item etc.
Castorix31 90,521 Reputation points

2022-09-09T19:38:55.52+00:00

How can I add another combo box items in this list? It can be very good if I use XAML. How can I place that combo box item on a specific position like on third item position or before the last item etc.

Like I did with devices.Insert(0, ... to insert the "System default" item at first position
Change 0 to another position (and other values for Name, etc...)
(MSDN doc : system.collections.generic.list-1.insert)
MERUN KUMAR MAITY 636 Reputation points

2022-09-10T14:00:11.263+00:00

Thank you very much sir, love the effort you put in to solve my queries. I accepted your answer.

But sorry to say that, I don't understand anything from your Microsoft (MSDN) links to understand the collection generic list. Because the Microsoft explanation is too much complex, not very easy like yours.

Suppose I want to insert a simple string, name "Selected application" on that audio device list at various position like in the last of that list, at second position and at third etc, the main purpose is, I have to find a specific way to insert anything at a specific position.

In my case I want to insert the "Selected application" in the last position of that audio device list , clicking upon this item my user redirected to a second WPF window.

Change 0 to another position (and other values for Name, etc...)

Sir, I already tried to do that by adding this code in after the "System default" string

devices.Add(new AudioDevice() { Name = "System default", Direction = "Playback", Id = sIdDefaultRender, Default = true });
devices.Add(new AudioDevice() { Name = "Selectd application" });

But it behave very strangely, I hope that this is appear in the second in that list but unfortunately it appears two three times I don't have any idea what happens.

Please give me your valuable code with proper explanation in pastebin like previous.
Castorix31 90,521 Reputation points

2022-09-10T15:56:59.213+00:00
But the doc is simple : it says "Inserts an element into the List<T> at the specified index."

So to add an item at the end, you add it at count-1, after the loop :

devices.Insert(devices.Count - 1, new AudioDevice() { Name = "MyItem", DisplayName = "Last Item", Direction = "Playback", Id = "Idlast", Default = false });
MERUN KUMAR MAITY 636 Reputation points

2022-09-10T17:01:03.037+00:00

Thank you very much sir, for your reply. I tried to add your given code after the complete of the for loop but unfortunately the code is not working.
Castorix31 90,521 Reputation points

2022-09-10T17:44:04.033+00:00

A simple test shows it works :
MERUN KUMAR MAITY 636 Reputation points

2022-09-10T19:17:35.107+00:00

Thank you very much sir, for your reply. You try to answer my every queries. And the best thing is, you never get irritated to my questions. I know sometimes I ask some idiotic question but you are a great teacher always remain calm.

Sir, your code is fully working and all of my problems are solved and now I can place any string at any places on that audio device list.

Sir, if you don't mind I ask another small question to you. In my previous comment I already told you that

I want to insert the "Selected application" in the last position of that audio device list , clicking upon this item my user redirected to a second WPF window.

My question is how Can I add a click event to that combo box items ? Because it's easier to add click event through XAML but in this case all the combo box items that means the audio device lists are added through code not through XAML.
Castorix31 90,521 Reputation points

2022-09-10T19:32:42.34+00:00

You already have the code : in cmb1_SelectionChanged event where you test device.Name...
MERUN KUMAR MAITY 636 Reputation points

2022-09-10T20:55:11.857+00:00

Thank you very much sir, for your reply. I understand that SelectionChanged event is something similar to the click event. But I don't know how to apply for a specific Combo box item? I already see the code and what I understand is, it can apply for a whole combo box not for a specific combo box item.

I give you demo question. Suppose I want to open another WPF window by clicking the last item on that combo box audio device list, how can I do that?

Can you give me the code snippet in pastebin like previous.

By the way, my programming carrier is really blessed because of teacher like you. Thank you once again.

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How to Add "System default" string in the postion of default audio device in WPF?

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