using System;
using System.Collections.Generic;
using System. ComponentModel;
using System. Drawing;
using System.Data;
using System. Linq;
using System. Text;
using System. Windows. Forms;
using System. Collections;
using System. Reflection;
using Newtonsoft.Json.Linq;
namespace ControlsAA
{
public class ComboBoxEx : ComboBox
{
TreeView lst = new TreeView();
public ComboBoxEx()
{
this.DrawMode = DrawMode.OwnerDrawFixed;//Only by setting this property as OwnerDrawFixed can redrawing work
lst.KeyUp += new KeyEventHandler(lst_KeyUp);
lst.MouseUp += new MouseEventHandler(lst_MouseUp);
// lst.KeyDown + = new KeyEventHandler(lst_KeyDown);
lst.Leave += new EventHandler(lst_Leave);
lst. CheckBoxes = true;
lst. ShowLines = false;
lst.ShowPlusMinus = false;
lst.ShowRootLines = false;
this.DropDownHeight = 1;
}
void lst_Leave(object sender, EventArgs e)
{
lst. Hide();
}
#region Property
[Description("Value of selected item"), Category("Data")]
public List<TreeNode> SelectedItems
{
get
{
List<TreeNode> lsttn = new List<TreeNode>();
foreach (TreeNode tn in lst.Nodes)
{
if (tn. Checked)
{
lsttn. Add(tn);
}
}
return lsttn;
}
}
/// <summary>
/// data source
/// </summary>
[Description("Data Source"), Category("Data")]
public object DataSource
{
get;
set;
}
/// <summary>
/// display field
/// </summary>
[Description("Display Field"), Category("Data")]
public string DisplayFiled
{
get;
set;
}
/// <summary>
/// value field
/// </summary>
[Description("Value field"), Category("Data")]
public string ValueFiled
{
get;
set;
}
#endregion
public void DataBind()
{
this. BeginUpdate();
if (DataSource != null)
{
if (DataSource is IDataReader)
{
DataTable dataTable = new DataTable();
dataTable.Load(DataSource as IDataReader);
DataBindToDataTable(dataTable);
}
else if (DataSource is DataView || DataSource is DataSet || DataSource is DataTable)
{
DataTable dataTable = null;
if (DataSource is DataView)
{
dataTable = ((DataView)DataSource).ToTable();
}
else if (DataSource is DataSet)
{
dataTable = ((DataSet)DataSource).Tables[0];
}
else
{
dataTable = ((DataTable)DataSource);
}
DataBindToDataTable(dataTable);
}
else if (DataSource is IEnumerable)
{
DataBindToEnumerable((IEnumerable)DataSource);
}
else
{
throw new Exception("DataSource doesn't support data type: " + DataSource. GetType(). ToString());
}
}
else
{
lst.Nodes.Clear();
}
lst.ItemHeight = this.ItemHeight;
lst.BorderStyle = BorderStyle.FixedSingle;
lst.Size = new Size(this.DropDownWidth, this.ItemHeight * (this.MaxDropDownItems - 1) - (int)this.ItemHeight / 2);
lst.Location = new Point(this.Left, this.Top + this.ItemHeight + 6);
this.Parent.Controls.Add(lst);
lst. Hide();
this. EndUpdate();
}
private void DataBindToDataTable(DataTable dt)
{
foreach (DataRow dr in dt.Rows)
{
TreeNode tn = new TreeNode();
if (!string.IsNullOrEmpty(DisplayFiled) & amp; & amp; !string.IsNullOrEmpty(ValueFiled))
{
tn.Text = dr[DisplayFiled].ToString();
tn.Tag = dr[ValueFiled].ToString();
}
else if (string. IsNullOrEmpty(ValueFiled))
{
tn.Text = dr[DisplayFiled].ToString();
tn.Tag = dr[DisplayFiled].ToString();
}
else if (string. IsNullOrEmpty(DisplayFiled))
{
tn.Text = dr[ValueFiled].ToString();
tn.Tag = dr[ValueFiled].ToString();
}
else
{
throw new Exception("ValueFiled and DisplayFiled must at least have a value");
}
tn. Checked = false;
lst.Nodes.Add(tn);
}
}
/// <summary>
/// Bind to an enumerable type
/// </summary>
/// <param name="enumerable">enumerable type</param>
private void DataBindToEnumerable(IEnumerable enumerable)
{
IEnumerator enumerator = enumerable. GetEnumerator();
while (enumerator. MoveNext())
{
object currentObject = enumerator. Current;
lst.Nodes.Add(CreateListItem(currentObject));
}
}
private TreeNode CreateListItem(Object obj)
{
TreeNode item = new TreeNode();
if (obj is string)
{
item. Text = obj. ToString();
item.Tag = obj.ToString();
}
else
{
if (DisplayFiled != "")
{
item.Text = GetPropertyValue(obj, DisplayFiled);
}
else
{
item. Text = obj. ToString();
}
if (ValueFiled != "")
{
item.Tag = GetPropertyValue(obj, ValueFiled);
}
else
{
item.Tag = obj.ToString();
}
}
return item;
}
private string GetPropertyValue(object obj, string propertyName)
{
object result = null;
result = ObjectUtil. GetPropertyValue(obj, propertyName);
return result == null ? String.Empty : result.ToString();
}
#region override
protected override void OnKeyUp(KeyEventArgs e)
{
base. OnKeyDown(e);
bool Pressed = (e.Control & amp; & amp; ((e.KeyData & amp; Keys.A) == Keys.A));
if (Pressed)
{
this.Text = "";
for (int i = 0; i < lst. Nodes. Count; i ++ )
{
lst.Nodes[i].Checked = true;
if (this. Text != "")
{
this.Text += ",";
}
this.Text + = lst.Nodes[i].Tag;
}
}
}
protected override void OnMouseDown(MouseEventArgs e)
{
this.DroppedDown = false;
}
protected override void OnMouseUp(MouseEventArgs e)
{
this.DroppedDown = false;
lst. Focus();
}
protected override void OnDropDown(EventArgs e)
{
string strValue = this. Text;
if (!string.IsNullOrEmpty(strValue))
{
List<string> lstvalues = strValue.Split(',').ToList<string>();
foreach (TreeNode tn in lst.Nodes)
{
if (tn.Checked & amp; & amp; !lstvalues.Contains(tn.Tag.ToString()) & amp; & amp; !string.IsNullOrEmpty(tn.Tag.ToString().Trim()))
{
tn. Checked = false;
}
else if (!tn.Checked & amp; & amp; lstvalues.Contains(tn.Tag.ToString()) & amp; & amp; !string.IsNullOrEmpty(tn.Tag.ToString().Trim()))
{
tn. Checked = true;
}
}
}
lst. Show();
}
#endregion
private void lst_KeyUp(object sender, KeyEventArgs e)
{
this.OnKeyUp(e);
}
private void lst_MouseUp(object sender, MouseEventArgs e)
{
try
{
this.Text = "";
for (int i = 0; i < lst. Nodes. Count; i ++ )
{
if (lst.Nodes[i].Checked)
{
if (this. Text != "")
{
this.Text += ",";
}
this.Text + = lst.Nodes[i].Tag;
}
}
}
catch
{
this.Text = "";
}
bool isControlPressed = (Control. ModifierKeys == Keys. Control);
bool isShiftPressed = (Control. ModifierKeys == Keys. Shift);
if (isControlPressed || isShiftPressed)
lst. Show();
else
lst. Hide();
}
}
/// <summary>
/// Object helper class
/// </summary>
public class ObjectUtil
{
/// <summary>
/// Get the property value of the object
/// </summary>
/// <param name="obj">May be a DataRowView or an object</param>
/// <param name="propertyName">property name</param>
/// <returns>Attribute value</returns>
public static object GetPropertyValue(object obj, string propertyName)
{
object result = null;
try
{
if (obj is DataRow)
{
result = (obj as DataRow)[propertyName];
}
else if (obj is DataRowView)
{
result = (obj as DataRowView)[propertyName];
}
else if (obj is JObject)
{
result = (obj as JObject).Value<JValue>(propertyName).Value; //.getValue(propertyName);
}
else
{
result = GetPropertyValueFormObject(obj, propertyName);
}
}
catch (Exception)
{
// Could not find this property
}
return result;
}
/// <summary>
/// Get the property value of the object
/// </summary>
/// <param name="obj">Object</param>
/// <param name="propertyName">property name ("Color", "BodyStyle" or "Info.UserName")</param>
/// <returns>Attribute value</returns>
private static object GetPropertyValueFormObject(object obj, string propertyName)
{
object rowObj = obj;
object result = null;
if (propertyName. IndexOf(".") > 0)
{
string[] properties = propertyName. Split('.');
object tmpObj = rowObj;
for (int i = 0; i < properties. Length; i ++ )
{
PropertyInfo property = tmpObj.GetType().GetProperty(properties[i], BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
if (property != null)
{
tmpObj = property. GetValue(tmpObj, null);
}
}
result = tmpObj;
}
else
{
PropertyInfo property = rowObj.GetType().GetProperty(propertyName, BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
if (property != null)
{
result = property. GetValue(rowObj, null);
}
}
return result;
}
}
}
c# multiple selection drop-down box (ComboBox) – Programmer Sought