3rdpartylibs/fastreports.wpf/FastReport.Forms.WPF/Controls/ComboBoxBase.cs

using CustomControls;

namespace System.Windows.Forms
{
    public class ComboBoxBase : ListControl
    {
        private CustomControls.OwnerDrawComboBox comboBox;
        private bool suppressSelectionChanged;

        public ComboBoxStyle DropDownStyle
        {
            get => comboBox.IsEditable ? ComboBoxStyle.DropDown : ComboBoxStyle.DropDownList;
            set
            {
                comboBox.IsEditable = value == ComboBoxStyle.DropDown;
                if (value == ComboBoxStyle.DropDownList)
                    comboBox.SetDropDownList();
            }
        }

        public override string Text
        {
            get => comboBox.ComboText;
            set
            {
                suppressSelectionChanged = true;
                if (comboBox.ComboText != value)
                {
                    comboBox.ComboText = value;
                    OnTextChanged(EventArgs.Empty);
                }
                comboBox.SelectedIndex = FindStringExact(value);
                suppressSelectionChanged = false;
            }
        }

        public int ItemHeight
        {
            get => (int)(comboBox.ItemHeight * DpiScale);
            set => comboBox.ItemHeight = (int)(value / DpiScale);
        }

        private DrawMode drawMode;
        public DrawMode DrawMode
        {
            get => drawMode;
            set
            {
                drawMode = value;
                if (value != DrawMode.Normal)
                    comboBox.SetOwnerDraw();
            }
        }

        public int DropDownWidth
        {
            get => (int)(comboBox.DropDownWidth * DpiScale);
            set => comboBox.DropDownWidth = value / DpiScale;
        }

        public int DropDownHeight
        {
            get => (int)(comboBox.MaxDropDownHeight * DpiScale);
            set => comboBox.MaxDropDownHeight = value / DpiScale;
        }

        public int MaxDropDownItems { get; set; } // TODO?

        public event DrawItemEventHandler DrawItem;
        public event MeasureItemEventHandler MeasureItem;
        public event EventHandler DropDown;
        public event EventHandler SelectionChangeCommitted;

        protected virtual void OnDrawItem(DrawItemEventArgs e) => DrawItem?.Invoke(this, e);

        protected virtual void OnMeasureItem(MeasureItemEventArgs e) => MeasureItem?.Invoke(this, e);

        protected virtual void OnDropDown(EventArgs e) => DropDown?.Invoke(this, e);

        protected override void OnSelectedIndexChanged(EventArgs e)
        {
            if (suppressSelectionChanged)
                return;

            // check if selected item is string: wrong behavior in FR PG object's combobox
            if (SelectedIndex != -1 && Items[SelectedIndex] is string)
                Text = Items[SelectedIndex].ToString();
            // reset Text: wrong behavior in FR Relation editor
            if (SelectedIndex == -1 && !comboBox.IsEditable)
                Text = null;
            base.OnSelectedIndexChanged(e);
            // this event fires when item is selected by the user
            if (comboBox.IsDropDownOpen)
            {
                // suppress side effects that may happen due to the user code in SelectionChangeCommitted
                suppressSelectionChanged = true;
                SelectionChangeCommitted?.Invoke(this, e);
                suppressSelectionChanged = false;
            }
        }

        protected override void SetControlHeight(int value)
        {
            // in SWF, this is controlled by the ItemHeight
        }

        protected void SetComboBox(CustomControls.OwnerDrawComboBox comboBox)
        {
            this.comboBox = comboBox;
            SetControl(comboBox);
            comboBox.IsEditable = true;
            comboBox.TextChanged += (sender, e) => OnTextChanged(e);
            comboBox.DrawItem += (sender, e) => OnDrawItem(e);
            comboBox.MeasureItem += (sender, e) => OnMeasureItem(e);
            comboBox.DropDownOpened += (sender, e) => OnDropDown(e);
        }

        public override void Refresh()
        {
            base.Refresh();
            var nullItem = comboBox.Template.FindName("nullItem", comboBox) as OwnerDrawItem;
            nullItem?.InvalidateVisual();
        }
    }
}