How Can I give Different Font size to the Uppercase characters of a string that binded to A List in WPF?

Question

Hi there, I have a WPF application where I use a ComboBox. My ComboBox ItemSource is bind to a List <> which I populate from C# in background.

Here is the C# code of that List<> :

   // Main code  
                 List devices = new List();  
             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);  
                     devices.Add(new AudioDevice() { Name = "System default", Direction = "Playback", Id = sIdDefaultRender, Default = true });  
                     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("	Direction : " + 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))  
                                 {  
                                     devices.Add(new AudioDevice() { Name = sFriendlyName, Direction = sDirection, Id = sId, Default = (sId == sIdDefaultRender || (sId == sIdDefaultCapture)) });  
                                     //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);  
                         }  
                     }  
                     devices.Insert(devices.Count - 0, new AudioDevice() { Name = "Selected application ...", Direction = "Recording", Id = "Idlast", Default = false });  
                 }  
                 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 string Id { get; set; }  
                     public bool Default { get; set; }  
      
         public override string ToString()  
                    {  
                        return Name;  
                    }  
      
                 }

If you carefully see the code then You see this line this.cmb1.ItemsSource = lcv; That means the List<> is added as ItemSource of the ComboBox, Now, I have a control template for comboBoxItem, my ComboBoxitem control template have lots of visual customisation and effects according to my choice.

Here is my ComboBoxItem controltemplate :

After adding this controltemplate in my ComboBoxitem, my comboBox looks amazing. My ComboBox content is added from a List<> not from a ComboBox item. If you carefully see this controltemplate, you can see this line , this is How I bind the List<> into my ComboBoxitem controltemplate.

All of my code run perfectly But my Main question is How Can I give different Font Size to the Uppercase characters and Lowercase characters of that string (The string is the Name which I get from the Class Audio device).

My approach is to separate Uppercase and Lowercase characters from that string "Name" using a IValueConverter. And then give bigger Font Size to the Uppercase converter and lower Font Size to the Lowercase converter.

Something like this :

I tried so many things like string builder, string replace but nothing works. Any other simple code suggestion is also welcome.

Answer

The strings are not fix length and the caps are in different positions so you'll need generate dynamic markup using C# not XAML. Do a Google search for dynamic inline style in WPF. However, I'm not sure if it's possible for a combobox to have an inline style. This is not possible in the web markup world. On web we have to use code (JavaScript) to create a custom component. I guess you'll need to do some research.
Let us know what you find.

Answer

Hi,@MERUN KUMAR MAITY . AgaveJoe's answer is great. Based on my research, it is difficult to return a specific font size for characters in variable length and variable content strings bound to controls.
A string does not have a font. If you are displaying a string as part of a control (such as a ComboBox) then how you format it depends on the functionality available within that control. If you are drawing that string as text on a display or in a printout, then you control the font that is used as part of the drawing commands.

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Answer

I can create a custom Text Block and override its text property.

using System.Windows;  
using System.Windows.Controls;  
using System.Windows.Documents;  
  
namespace WpfApp1;  
  
public class CustomTextBlock : TextBlock  
{  
    public new string Text  
    {  
        get => (string)GetValue(TextProperty);  
        set => SetValue(TextProperty, value);  
    }  
  
    // Using a DependencyProperty as the backing store for Text.  This enables animation, styling, binding, etc...  
    public static new readonly DependencyProperty TextProperty =  
        DependencyProperty.Register("Text", typeof(string), typeof(CustomTextBlock), new PropertyMetadata(null, (d, ea) =>  
        {  
            if (d is TextBlock textBlock)  
            {  
                textBlock.Inlines.Clear();  
  
                if (ea.NewValue is string value)  
                {  
                    foreach (char c in value)  
                    {  
                        textBlock.Inlines.Add(new Run { FontSize = GetFontSize(c), Text = c.ToString() });  
                    }  
                }  
            }  
        }));  
  
    private static double GetFontSize(char c)  
    {  
        // You can add your other logic here  
        /*if (c == '#')  
        {  
            return 5;  
        }  
  
        if (char.IsNumber(c))  
        {  
            return 22;  
        }*/  
  
        if (char.IsUpper(c))  
        {  
            return 18;  
        }  
  
        return 10;  
    }  
}

I can use it in my XAML this way. I used the CustomTextBlock in the ComboBox ItemTemplate but I think it should also work in the ComboBoxItem ControlTemplate.

  
      
          
              
                  
                    Some Item #0  
                    Some Item #1  
                    Some Item #2

In my ComboBoxItem ControlTemplate it can be used like below.

This is a part of my ComboBoxItem ControlTemplate code where I do the Binding with Name and apply the CustomTextBlock.

How Can I give Different Font size to the Uppercase characters of a string that binded to A List in WPF?

3 answers