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Can sfComboBox use named tuples for value and display members ?

Hello,


A sfComboBox with a SortedSet of named tuples will throw an exception when .ValueMember and .DisplayMember set.

Designer settings
  • DropDownStyle is DropDownList
  • AllowSelectAll is true
  • ComboBoxMode is MultiSelection
The following will throw an Exception "System.NullReferenceException: 'Object reference not set to an instance of an object.'
" when the drop down list opened by user.

Dates = new SortedSet<(DateTime val,string show)>();
DateTime dt;
dt = DateTime.Parse("01/01/2019 12:00:00"); Dates.Add((val: dt, show: dt.ToString("D")));
dt = DateTime.Parse("02/01/2019 12:00:00"); Dates.Add((val: dt, show: dt.ToString("D")));
dt = DateTime.Parse("01/15/2019 12:00:00"); Dates.Add((val: dt, show: dt.ToString("D")));

sf_comboBox1.DataSource = Dates;
sf_comboBox1.ValueMember = "val";
sf_comboBox1.DisplayMember = "show";

When the member settings are not assigned, the drop down list shows check boxes with the tuple rendering (without names)

☐ Select All
☐ (01/01/2019 12:00:00 PM, Tuesday, January 1, 2019)
☐ (01/15/2019 12:00:00 PM, Tuesday, January 15, 2019)
☐ (02/01/2019 12:00:00 PM, Friday, February, 2019)
      
What I want in the drop down list is just the "D" formatted datetime without parenthesis


thanks
iosman

3 Replies

VR Vijayalakshmi Roopkumar Syncfusion Team November 12, 2019 12:12 PM UTC

Hi iosman

Thank you for your patience.

In our Syncfusion SfComboBox control, there is no SortedSet feature .So when we bind the datasource with DisplayMember and ValueMember property, it will throw the null exception. You can restrict this NRE crash using the following code:

Code Example:[C#]

 
 
  
sfComboBox1.DataSource = Dates.Select(x => x.show).ToList();   
  
 

We have also attached the sample for your reference below:

Samplehttps://www.syncfusion.com/downloads/support/directtrac/149011/ze/SfComboBox-1200953919
 

Please try this solution and let us know if it is helpful for you.

Regards
Vijayalakshmi V.R. 
 



IM ios man replied to ios man November 16, 2019 06:22 AM UTC

Hello,


A sfComboBox with a SortedSet of named tuples will throw an exception when .ValueMember and .DisplayMember set.

Designer settings
  • DropDownStyle is DropDownList
  • AllowSelectAll is true
  • ComboBoxMode is MultiSelection
The following will throw an Exception "System.NullReferenceException: 'Object reference not set to an instance of an object.'
" when the drop down list opened by user.

Dates = new SortedSet<(DateTime val,string show)>();
DateTime dt;
dt = DateTime.Parse("01/01/2019 12:00:00"); Dates.Add((val: dt, show: dt.ToString("D")));
dt = DateTime.Parse("02/01/2019 12:00:00"); Dates.Add((val: dt, show: dt.ToString("D")));
dt = DateTime.Parse("01/15/2019 12:00:00"); Dates.Add((val: dt, show: dt.ToString("D")));

sf_comboBox1.DataSource = Dates;
sf_comboBox1.ValueMember = "val";
sf_comboBox1.DisplayMember = "show";

When the member settings are not assigned, the drop down list shows check boxes with the tuple rendering (without names)

☐ Select All
☐ (01/01/2019 12:00:00 PM, Tuesday, January 1, 2019)
☐ (01/15/2019 12:00:00 PM, Tuesday, January 15, 2019)
☐ (02/01/2019 12:00:00 PM, Friday, February, 2019)
      
What I want in the drop down list is just the "D" formatted datetime without parenthesis


thanks
iosman

thanks my issue has been fixed ...








VR Vijayalakshmi Roopkumar Syncfusion Team November 18, 2019 05:09 AM UTC

Hi ios,

Thank you for your update.

We are glad to hear that your problem with SfComboBox has been solved by our solution.

Please let us know if you need any further assistance on this.

Regards
Vijayalakshmi V.R.

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