C# Combobox double databinding - select item based on entityframework value

Question

I have few tables, using Entity Framework 6. My goal is to bind class table1 to ComboBox Value Member

ComboBox DataSource is:

ComboBoxBasicDB[] statType = new ComboBoxBasicDB[] {
            new ComboBoxBasicDB { Text = "A1", Value = 0 },
            new ComboBoxBasicDB { Text = "A2", Value = 1 },
            new ComboBoxBasicDB { Text = "A3", Value = 2 },
            new ComboBoxBasicDB { Text = "A4", Value = 4 },
            new ComboBoxBasicDB { Text = "B12", Value = 12 },
            new ComboBoxBasicDB { Text = "B13", Value = 13 },
            new ComboBoxBasicDB { Text = "B14", Value = 14 }
        };

statBS.DataSource = statType; // statBS == BindingSource, configured throught VS designer, comboBox.DataSource = statBS, comboBox.ValueMember = Value, comboBox.DisplayMember = Text

table1 contains property called ex. Value1 which contains one of these (0, 1, 2, 4, 12, 13, 14)

What am I trying to do is to load from DB row and use something like this on TextBox:

textBox.DataBindings.Add("Text", binding, "Name");

which works perfectly

I tried something like this:

comboBox.DataBindings.Add("SelectedValue", binding, "Value1");

but it not working, nothing is selected after query. textBox bind successfully

I used SelectedIndex but there is going one problem, and that is value above 7, because there are 7 items in statType not 14.

I hope you understand what am I trying to do :/ I thought I could do that throught comboBox.DataManager but its private

Thanks for any ideas.

Have you tried [this answer from SO](http://stackoverflow.com/a/10015963/4677585) — wonderbell, Mar 21 '16 at 20:47
as I said I tried this: comboBox.DataBindings.Add("SelectedValue", binding, "Value1"); not working :/ Even If I try it with button action as comboBox.SelectedValue = 14; — user1085907, Mar 21 '16 at 21:07

score 0 · Accepted Answer · answered Mar 22 '16 at 11:21

So solution is custom implementation, in mentioned DataBindings change SelectedValue to SelectedItemValue

Implementation:

public class ComboBoxBasic : ComboBox
{
    bool diffTextColor = false;

    public ComboBoxBasic()
    {

    }

    public object SelectedItemValue
    {
        get
        {
            return (SelectedItem as ComboBoxBasicDB).Value;
        }

        set
        {
            for(int i = 0; i < Items.Count; i++)
            {
                ComboBoxBasicDB item = Items[i] as ComboBoxBasicDB;

                if(item.Value.ToString() == value.ToString())
                {
                    SelectedIndex = i;

                    break;
                }
            }
        }
    }

    public bool DifferentTextColor
    {
        get { return diffTextColor; }

        set
        {
            diffTextColor = value;

            if (diffTextColor)
            {
                DrawItem += ComboBoxBasic_DrawItem;
                DrawMode = DrawMode.OwnerDrawFixed;
            }
            else
                DrawItem -= ComboBoxBasic_DrawItem;
        }
    }

    void ComboBoxBasic_DrawItem(object sender, DrawItemEventArgs e)
    {
        e.DrawBackground();

        if (e.State == DrawItemState.Focus)
            e.DrawFocusRectangle();

        Brush brush = new SolidBrush((sender as Control).ForeColor);

        ComboBoxBasicDB item = (sender as ComboBoxBasic).Items[e.Index] as ComboBoxBasicDB;

        if (item.ForeColor != Brushes.Black)
            brush = item.ForeColor;

        e.Graphics.TextRenderingHint = System.Drawing.Text.TextRenderingHint.ClearTypeGridFit;
        e.Graphics.DrawString(item.Text, (sender as Control).Font, brush, e.Bounds.X, e.Bounds.Y);
    }
}

Also there is custom DrawItem if its enabled by DifferentTextColor

C# Combobox double databinding - select item based on entityframework value

1 Answers1