C# DataGridView Not Updated When Datasource Is Changed

Answer :

Quick and dirty solution:

dataGridView.DataSource = null; dataGridView.DataSource = phase3Results; 

Clean and correct solution:

Use a BindingList<T> instead of List<T> as your DataSource. List<T> does not fire events when its collection changes.

Also, if you additionally implement INotifyPropertyChanged for T, BindingList<T> automatically subscribes to property changes for each T in the collection and lets the view know about the change.

Try using a BindingList<> instead of List<> and (as already suggested by Daniel), implement INotifyPropertyChanged. However, I think you can also call .Refesh() if you didn't want to implement the INotifyPropertyChanged interface.

Here's an example ripped from here

public class Car : INotifyPropertyChanged  {    private string _make;    private string _model;    private int _year;    public event PropertyChangedEventHandler PropertyChanged;    public Car(string make, string model, int year)    {      _make = make;      _model = model;      _year = year;    }    public string Make    {      get { return _make; }      set      {        _make = value;        this.NotifyPropertyChanged("Make");      }    }    public string Model    {      get { return _model; }      set      {        _model = value;        this.NotifyPropertyChanged("Model");      }    }    public int Year    {      get { return _year; }      set      {        _year = value;        this.NotifyPropertyChanged("Year");      }    }    private void NotifyPropertyChanged(string name)    {      if(PropertyChanged != null)        PropertyChanged(this, new PropertyChangedEventArgs(name));    }  }  _dgCars.AutoGenerateColumns = false;  DataGridViewTextBoxColumn makeColumn = new DataGridViewTextBoxColumn();  makeColumn.DataPropertyName = "Make";  makeColumn.HeaderText = "The Car's Make";  DataGridViewTextBoxColumn modelColumn = new DataGridViewTextBoxColumn();  modelColumn.DataPropertyName = "Model";  modelColumn.HeaderText = "The Car's Model";  DataGridViewTextBoxColumn yearColumn = new DataGridViewTextBoxColumn();  yearColumn.DataPropertyName = "Year";  yearColumn.HeaderText = "The Car's Year";  _dgCars.Columns.Add(makeColumn);  _dgCars.Columns.Add(modelColumn);  _dgCars.Columns.Add(yearColumn);  BindingList<Car> cars = new BindingList<Car>();  cars.Add(new Car("Ford", "Mustang", 1967));  cars.Add(new Car("Shelby AC", "Cobra", 1965));  cars.Add(new Car("Chevrolet", "Corvette Sting Ray", 1965));  _dgCars.DataSource = cars; 

You need to implement the INotifyPropertyChanged interface on the object that is storing the data. Each property needs to raise that event during the set call of a property if the value changed. Then the grid will automatically get the update.