C# ListControl.ClearSelection方法代码示例

 public static void SafeSelect(ListControl ddl, string val)
 {
     ListItem li = ddl.Items.FindByValue(val);
     if (li != null)
     {
         ddl.ClearSelection();
         li.Selected = true;
     }
 }

 public static bool TrySelect(ListControl list, string text, string value, ref ListItem li)
 {
     li = null;
     if (string.IsNullOrEmpty(value)) return false;
     li = list.Items.FindByValue(value);
     if (li != null)
     {
         list.ClearSelection();
         li.Selected = true;
     }
     return (li != null);
 }

 public static ListItem SelectAdd(ListControl list, string text, string value)
 {
     ListItem li = list.Items.FindByValue(value);
     if (li == null)
     {
         li = new ListItem(text, value);
         list.Items.Add(li);
     }
     list.ClearSelection();
     li.Selected = true;
     return li;
 }

        /// <summary>
        /// Selects the item in the list control that contains the specified value, if it exists.
        /// </summary>
        /// <param name="dropDownList"></param>
        /// <param name="selectedValue">The value of the item in the list control to select</param>
        /// <returns>Returns true if the value exists in the list control, false otherwise</returns>
        public static bool SetSelectedValue(ListControl dropDownList, String selectedValue)
        {
            if (dropDownList != null)
            {
                dropDownList.ClearSelection();

                ListItem selectedListItem = dropDownList.Items.FindByValue(selectedValue);

                if (selectedListItem != null)
                {
                    selectedListItem.Selected = true;
                    return true;
                }
            }

            return false;
        }

 public static bool SelectedByValue(ListControl lst, string strValue)
 {
     ListItem item = lst.Items.FindByValue(strValue);
     if (item == null)
     {
         return false;
     }
     if ((lst.GetType().ToString() != "System.Web.UI.WebControls.ListBox") && (lst.GetType().ToString() != "System.Web.UI.WebControls.CheckBoxList"))
     {
         lst.ClearSelection();
     }
     item.Selected = true;
     return true;
 }

        public static void SelectListItemByValue(ListControl dropDownList, object value, object defaultValue)
        {
            if (dropDownList == null)
                return;

            dropDownList.ClearSelection();

            var selectedItem = dropDownList.Items.FindByValue(value == null ? (defaultValue == null ? string.Empty : defaultValue.ToString()) : value.ToString());

            if (selectedItem != null)
                selectedItem.Selected = true;
        }

        /// <summary>列表框</summary>
        /// <param name="entity"></param>
        /// <param name="field"></param>
        /// <param name="control"></param>
        /// <param name="canSave"></param>
        protected virtual void SetFormItemListControl(IEntity entity, FieldItem field, ListControl control, Boolean canSave)
        {
            if (control.Items.Count < 1 || !String.IsNullOrEmpty(control.DataSourceID))
            {
                control.DataBind();
                // 这个赋值会影响RequiresDataBinding，而RequiresDataBinding会导致列表控件在OnPreRender阶段重新绑定，造成当前设定的值丢失。
                //control.AppendDataBoundItems = false;
            }
            if (control.Items.Count < 1) return;

            String value = String.Empty + entity[field.Name];
            try
            {
                control.SelectedValue = value;
                if (control.GetType() == typeof(DropDownList) || control.GetType() == typeof(ListControl))
                {
                    /*
                     * 对于ListControl和DropDownList,仅PostBack时有可能抛出异常,初次打开有可能在PerformDataBinding中抛出异常,所以要做额外检测
                     *
                     * 因为DropDownList.SelectedIndex get时有可能修改Items[0].Selected, 所以下面代码最好避免访问SelectedIndex,SelectedValue
                     *
                     * 对于XControl.DropDownList始终没问题
                     * */

                    var selected = false;
                    for (int i = 0; i < control.Items.Count; i++)
                    {
                        var item = control.Items[i];
                        if (item.Selected)
                        {
                            selected = item.Value == value;
                            break;
                        }
                    }
                    if (!selected)
                    {
                        // 没有任何选中项或选中项不是设置的值
                        throw new ArgumentException();
                    }
                }
            }
            catch (ArgumentException)
            {
                var li = control.Items.FindByValue(value);
                if (li == null)
                {
                    li = new ListItem(value, value);
                    control.Items.Add(li);
                }
                control.ClearSelection();
                li.Selected = true;
            }
        }

		/// <summary>
		/// Tenta selecionar o valor especificado no controle de lista.
		/// </summary>
		/// <param name="ctl">O <see cref="ListControl"/></param>
		/// <param name="val">O valor.</param>
		/// <param name="throwException">Se verdadeiro, uma exceção é lançada, ao invés de simplesmente returnar <c>false</c>.</param>
		/// <returns>Verdadeiro se o valor pôde ser atribuído, falso caso contrário</returns>
		/// <exception cref="IndexOutOfRangeException">Se o valor não for encontrado no <see cref="ListControl"/> especificado em <paramref name="ctl"/>.</exception>
		public static bool TrySetValue(ListControl ctl, string val, bool throwException)
		{
			ListItem li = ctl.Items.FindByValue(val);
			if (li == null) 
			{
				if (throwException)
					throw new IndexOutOfRangeException(String.Format("O valor '{0}' não foi encontrado no {1} '{2}'.", val, ctl.GetType().Name, ctl.ID));
				else if (!IsSingleSelectionControl(ctl))
					ctl.ClearSelection();
			}
			else
			{
				if (IsSingleSelectionControl(ctl))
					ctl.SelectedValue = li.Value;
				else
					li.Selected = true;
			}

			return li != null;
		}

 /// <summary>
 /// 设置ListControl选中项
 /// </summary>
 /// <param name="listControl">ListControl控件</param>
 /// <param name="selectValue">选中的Value</param>
 public static void SetSelectedByValue(ListControl listControl, string selectValue)
 {
     listControl.ClearSelection();
     ListItem li = listControl.Items.FindByValue(selectValue);
     if (li != null)
     {
         li.Selected = true;
     }
 }

 /// <summary>
 /// 设置ListControl选中项
 /// </summary>
 /// <param name="listControl">ListControl控件</param>
 /// <param name="selectValue">选中的Value</param>
 /// <param name="separator">分隔符</param>
 public static void SetMultSelectedByValue(ListControl listControl, string selectValue, string separator)
 {
     listControl.ClearSelection();
     string[] vals = selectValue.Split(new string[]{ separator}, StringSplitOptions.RemoveEmptyEntries);
     foreach (ListItem li in listControl.Items)
     {
         li.Selected = vals.Contains(li.Value);
     }
 }

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 /// </summary>
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 /// <param name="e">ί���¼�����</param>
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 public static ListItem SetListControlSafely(ListControl listCtrl, string value, string text, bool addIfNotExists, bool addEmptyItem, EventHandler eventHandler, EventArgs e)
 {
     if (listCtrl == null) {
         return null;
     }
     ListItem li = null;
     if (value != null) {
         li = listCtrl.Items.FindByValue(value);
         if (li == null && addIfNotExists) {
             if (string.IsNullOrEmpty(text)) {
                 text = string.Format("({0})", value);
             }
             li = new ListItem(text, value);
         }
     }
     if (addEmptyItem) {
         listCtrl.Items.Insert(0, string.Empty);
     }
     if (li != null) {
         listCtrl.ClearSelection();
         li.Selected = true;
         if (eventHandler != null) {
             eventHandler(listCtrl, e);
         }
     }
     return li;
 }