Getting ArgumentNullException was unhandled

[Sabuj]

I am using Radgridview in my WPF app. The view model implements Idataerrorinfo interface. Whenever I add a new row to the radGridview I get that exception from a file called Disassembly.  Any idea what might cause this error.

Here is a screen shot

[Vlad]

Hello,

 Can you post the stack trace?

Regards,
Vlad
the Telerik team

[Sabuj]

Attached with this  is the stack trace.

I was using idataerrorinfor interface for validation which I think has caused the problem. However I am just guessing. It might not be true. 

[Pavel Pavlov]

Hello Sabuj ,

Thanks for pasting the StackTrace !  Indeed the problem seems to be connected with validation .
Can you also paste the code for your ViewModel . I will try gather a small repro app here with your view model .
Once I am able to reproduce it here, either a workaround or a fix will be provided.

Kind regards,
Pavel Pavlov
the Telerik team

[Sabuj]

Thanks for your reply

Here is one of the view model

class AddConfigPropertyViewModel:ViewModelBase//,IDataErrorInfo

    {

 

        #region Private Variable

        private List<string> _dataType;

        private ObservableCollection<ConfigViewModel> _allConfig;

        private string _configProperty;

        #endregion

 

        #region Constructor

        public AddConfigPropertyViewModel(AddConfigWindow window)

        {

            //AddConfigWindow window = new AddConfigWindow();

            // TODO: Complete member initialization

            this.AddConfigWindow = window;

        }

        #endregion

 

        #region Properties

        public AddConfigWindow AddConfigWindow { get; set; }

        public string ConfigPropertyName

        {

            get

            {

                if (_configProperty == null)

                {

                    _configProperty = "";

                }

 

                return _configProperty;

            }

            set

            {

                _configProperty = value;

            }

        }

        public List<string> DataType

        {

            get

            {

                if (_dataType == null)

                {

                    _dataType = new List<String>();

                    _dataType.Add("String");

                    _dataType.Add("Number");

                }

                return _dataType;

            }

 

            set

            {

                _dataType = value;

            }

        }

 

        public ObservableCollection<ConfigViewModel> AllConfig

        {

            get

            {

                if (_allConfig == null)

                {

                    _allConfig = new ObservableCollection<ConfigViewModel>();

                }

                return _allConfig;

            }

            set

            {

                _allConfig = value;

                OnPropertyChanged("AllConfig");

            }

        }

 

         

        

        private int CurrentCollectionIndex { get; set; }

        private IEnumerable<ConfigurationProperty> Collection { get; set; }

        public bool IsControlAtTheTop { get; set; }

        #endregion

 

        #region Validation

     

 

        #endregion

 

        #region Icommand

 

        public ICommand GetConfigProperty { get { return new RelayCommand(GetConfigPropertyExecute, CanGetConfigPropertyExecute); } }

 

        bool CanGetConfigPropertyExecute()

        {

            return true;

        }

 

        void GetConfigPropertyExecute()

        {

            _allConfig = new ObservableCollection<ConfigViewModel>();

            Collection = Global.DbContext.ConfigurationProperties.

                                    Where(con => con.chrCPProperty.Contains(ConfigPropertyName)

                                        && con.chrCPProperty != "").ToList();

            //Collection = allConfigResult;

            _allConfig = AllConfig;

            _allConfig.Clear();

            int index;

            Console.Write(Collection.Count());

            for (index = 0; index  < Collection.Count(); index++)

            {

                _allConfig.Add(new ConfigViewModel(Collection.ElementAt(index)));

            }

            CurrentCollectionIndex = index;

            AllConfig = _allConfig;

            //OnPropertyChanged("AllConfig");

        }

 

 

        public ICommand AddNewConfigProperty { get { return new RelayCommand(AddNewConfigPropertyExecute, CanAddNewConfigPropertyExecute); } }

 

        bool CanAddNewConfigPropertyExecute()

        {

            //if(!HasErrors)

                return true;

            //return false;

        }

 

        void AddNewConfigPropertyExecute()

        {

            ConfigurationProperty newConfigProperty = new ConfigurationProperty();

            Global.DbContext.ConfigurationProperties.AddObject(newConfigProperty);

            ConfigViewModel cfgModel = new ConfigViewModel(newConfigProperty);

            cfgModel.IsInValid = true;

            AllConfig.Add(cfgModel);

        }

         

        public ICommand SaveConfig { get { return new RelayCommand(SaveConfigExecute, CanSaveConfigExecute); } }

        bool CanSaveConfigExecute()

        {

            if (this.AllConfig.Any(con=>con.IsInValid))

            {

                return false;

            }

            else

            {

                return true;

            }

        }

 

        void SaveConfigExecute()

        {

            try

            {

                Global.DbContext.SaveChanges();

                MessageBox.Show("Saved!");

            }

            catch (Exception ex)

            {

                MessageBox.Show(ex.ToString());

            }

        }

 

        public ICommand CancelConfig { get { return new RelayCommand(CancelConfigExecute, CanCancelConfigExecute); } }

 

        bool CanCancelConfigExecute()

        { 

            return true;

        }

 

        void CancelConfigExecute()

        {

            AddConfigWindow.Close();

        }

        #endregion

    }

        Another View model

class ConfigViewModel : ViewModelBase, IDataErrorInfo

{

     

 

    #region private variables

 

    private ConfigurationProperty _configurationPropertyEntity;

    //private string _configPropertyName;

    private static List<string> _existingConfigPropertyList;

     

    //private bool _hasError;

    private List<string> _dataType;

    #endregion

 

    #region constructor

 

    public ConfigViewModel(ConfigurationProperty configEntity)

    {

        ConfigurationPropertyEntity = configEntity;

        IsInValid = false;

    }

    #endregion

 

    #region properties

    public List<string> DataType

    {

        get

        {

            if (_dataType == null)

            {

                _dataType = new List<String>();

                _dataType.Add("String");

                _dataType.Add("Number");

            }

            return _dataType;

        }

        set

        {

            _dataType = value;

        }

    }

 

 

    public bool IsInValid

    {

        get;

        set;

    }

    [Required(ErrorMessage = "Field 'PartConfigName' is required.")]

    public string PartConfigName

    {

 

        get

        {

            //if (ConfigurationPropertyEntity == null || ConfigurationPropertyEntity.chrCPProperty == null)

            //{

            //    _configPropertyName = "";

            //}

            //else

            //{

            //    _configPropertyName = ConfigurationPropertyEntity.chrCPProperty;

            //}

            return ConfigurationPropertyEntity.chrCPProperty;

        }

        set

        {

            IsInValid = true;

            if (value == string.Empty || value == "")

                throw new ArgumentException("Name cannot be null or empty");

            else if (ExistingConfigPropertyList.Where(con => con == value).Count() > 0)

            {

                throw new ArgumentException("Config prop already exist");

                //result = "Config prop already exist";

                //System.IO.File.AppendAllText("C:\\temp\\log.txt", "PartConfigName: " + PartConfigName + "\r\n");

            }

            else

            {

                IsInValid = false;

                ConfigurationPropertyEntity.chrCPProperty = value;

                _existingConfigPropertyList = ExistingConfigPropertyList;

                _existingConfigPropertyList.Add(ConfigurationPropertyEntity.chrCPProperty);

                ExistingConfigPropertyList = _existingConfigPropertyList;

                //Global.DbContext.ConfigurationProperties.AddObject(ConfigurationPropertyEntity);

            }

            OnPropertyChanged("PartConfigName");  

        }

    }

 

    public string ValidationMessage { get; set; }

    public ConfigurationProperty ConfigurationPropertyEntity

    {

        get

        {

            return _configurationPropertyEntity;

        }

 

        set

        {

            _configurationPropertyEntity = value;

        }

 

    }

 

    public string SelectedDataType

    {

        get

        {

            if (ConfigurationPropertyEntity.bitCPIsNumeric)

                return "Number";

            else

                return "String";

        }

        set

        {

            if (String.Compare(value, "Number") == 0)

                ConfigurationPropertyEntity.bitCPIsNumeric = true;

            else

                ConfigurationPropertyEntity.bitCPIsNumeric = false;

            OnPropertyChanged("SelectedDataType");

        }

    }

     

    public static List<string> ExistingConfigPropertyList

    {

        get

        {

            if (_existingConfigPropertyList == null)

            {

               _existingConfigPropertyList = new List<string>();

                var configPropertyList = Global.DbContext.ConfigurationProperties.Select(con => con.chrCPProperty);

                _existingConfigPropertyList = configPropertyList.ToList();

            }

            return _existingConfigPropertyList;

        }

        set

        {

            _existingConfigPropertyList = value;

            //OnPropertyChanged("ExistingConfigPropertyList");

        }

    }

 

     

    #endregion

 

    #region validation

    public string Error

    {

        get { throw new NotImplementedException(); }

 

    }

 

    public string this[string columnName]

    {

        get

        {

            string result = null;

           


                if (columnName == "PartConfigName")

                {

                    if (string.IsNullOrEmpty(PartConfigName))

                        result = "Please enter a name";

                    else if (ExistingConfigPropertyList.Where(con => con == PartConfigName).Count() > 1)

                    {

                        result = "Config prop already exist";

                        //System.IO.File.AppendAllText("C:\\temp\\log.txt", "PartConfigName: " + PartConfigName + "\r\n");

                    }

                   


                }

            return result;

        }

    }

 

    #endregion

}

[Pavel Pavlov]

Hello Sabuj ,

We were trying to reproduce the problem locally using your code. However still we were not able to get the exception you have mentioned.  As alternative I may offer the following way to further assist you: If you can attach a small repro project that exposes the exception I will be glad to debug it and get back to you with either a workaround or a fix.

Regards,
Pavel Pavlov
the Telerik team

[Sabuj]

Thanks for your reply. Right now is not possible for me to create a small repro project. However I have work around the issue and it works okay. I have another question though, will post seperate ticket for it.