下拉框在PropertyGrid的用法

本文主要是介绍下拉框在PropertyGrid的用法，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

本例子在项目中已试验通过。

直接看代码例子：

 #region bill of material drop-down list 
    public class DropDownListBillConverter : System.Drawing.Design.UITypeEditor
    {
        public override UITypeEditorEditStyle GetEditStyle(ITypeDescriptorContext context)
        {
            return System.Drawing.Design.UITypeEditorEditStyle.DropDown;
        }
        
        public override object EditValue(ITypeDescriptorContext context, IServiceProvider provider, object value)
        {
            System.Windows.Forms.Design.IWindowsFormsEditorService iws = (System.Windows.Forms.Design.IWindowsFormsEditorService)provider.GetService(typeof(System.Windows.Forms.Design.IWindowsFormsEditorService));
            if (iws != null)
            {
                DropDownListBillControll dlc = new DropDownListBillControll(iws,value);
                iws.DropDownControl(dlc);
                return (Bill)dlc.SelectedItem;
            }
            return value;
        }
    }
    public class DropDownListBillControll : System.Windows.Forms.ListBox
    {
        public DropDownListBillControll(System.Windows.Forms.Design.IWindowsFormsEditorService iws,object value)
        {
            //inite dropdownlist value 
            DataSet ds = FormDesignerDataAccess.BomGroups;
            
            if (ds != null && ds.Tables[0]!=null && ds.Tables[0].Rows.Count>0)
            {
                foreach (DataRow dr in ds.Tables[0].Rows)
                {
                    Bill b = new Bill();
                    b.GroupId = dr["GroupId"].ToString();
                    b.GroupName = dr["GroupName"].ToString();
                    this.Items.Add(b);
                }                
            }
            if (value != null)
            {
                string selectevalue = ((Bill)value).GroupId;
                for (int i = 0; i < this.Items.Count; i++)
                {
                    if (((Bill)this.Items[i]).GroupId == selectevalue)
                    {
                        this.SelectedIndex = i;
                        break;
                    }
                }
            }
            this._iws = iws;
            this.Visible = true;
            this.BorderStyle = System.Windows.Forms.BorderStyle.None;
            this.SelectedValueChanged += new EventHandler(cb_SelectedValueChanged);
            this.DisplayMember = "GroupName";
            this.ValueMember = "GroupId";
        }
        
        private System.Windows.Forms.Design.IWindowsFormsEditorService _iws;
        private void cb_SelectedValueChanged(object sender, EventArgs e)
        {
            if (this.SelectedItem != null)
            {
                //this.select = (Bill)this.SelectedItem; 
                this._iws.CloseDropDown();
            }
        }
    }
    public class Bill
    {
        public string GroupId{get;set;}
        public string GroupName{get;set;}
        public override string ToString()
        {
            return GroupName; 
        }
    } 
    #endregion
 

用法如下：

 public class BillOfMaterialsQuestion : IQuestion
    {
        /// <summary> 
        /// If this question is required. 
        /// </summary> 
        [DescriptionAttribute("If this question is required.")]
        public bool Required { get; set; }
        private Bill m_Part;
        [ReadOnlyAttribute(false),
        BrowsableAttribute(true),
        EditorAttribute(typeof(DropDownListBillConverter), typeof(System.Drawing.Design.UITypeEditor)),
        DescriptionAttribute("Parts list")
        ]
        public Bill Part
        {
            get { return m_Part; }
            set { m_Part = value; }
        }
        public BillOfMaterialsQuestion()
        {
             
        }
    }
 