ComboBox SelectedValue property doesn't work

I'm trying to add objects into a combobox and use SelectedValue property to select and item in the combobox but it does not work: SelectedValue is still null after the assignment.

        class ComboBoxItem
        {
            string name;
            object value;

            public string Name { get { return name; } }
            public object Value { get { return value; } }

            public ComboBoxItem(string name, object value)
            {
                this.name = 开发者_运维技巧name;
                this.value = value;
            }

            public override bool Equals(object obj)
            {
                ComboBoxItem item = obj as ComboBoxItem;
                return item!=null && Value.Equals(item.Value);
            }
        }          

            operatorComboBox.Items.Add(new ComboBoxItem("Gleich", SearchOperator.OpEquals));
            operatorComboBox.Items.Add(new ComboBoxItem("Ungleich", SearchOperator.OpNotEquals));


            operatorComboBox.ValueMember="Value";
            //SelectedValue is still null after this statement
            operatorComboBox.SelectedValue = SearchOperator.OpNotEquals; 

ValueMember is only applicable when databinding via DataSource property, not when you add items manually with Items.Add. Try this:

var items = new List<ComboBoxItem>();
items.Add(new ComboBoxItem(...));

operatorComboBox.DataSource = items;

Btw, note that when you override Equals, you should also override and implement GetHashCode.