Question

我创建了一个继承自RadioButtonList的类，以便为每个列表项添加GroupName属性。（为什么它不存在我已经不知道了。）

这在渲染时按预期工作，但不会在回发时保留选定的项目。

public class GroupedRadioButtonList : RadioButtonList
{
    [Bindable(true), Description("GroupName for all radio buttons in list.")]
    public string GroupName
    {
        get;
        set;
    }

    protected override void RenderItem(ListItemType itemType, int repeatIndex, RepeatInfo repeatInfo, System.Web.UI.HtmlTextWriter writer)
    {
        RadioButton radioButton = new RadioButton();
        radioButton.Page = this.Page;
        radioButton.GroupName = this.GroupName;
        radioButton.ID = this.ClientID + "_" + repeatIndex.ToString();
        radioButton.Text = this.Items[repeatIndex].Text;
        radioButton.Attributes["value"] = this.Items[repeatIndex].Value;
        radioButton.Checked = this.Items[repeatIndex].Selected;
        radioButton.TextAlign = this.TextAlign;
        radioButton.AutoPostBack = this.AutoPostBack;
        radioButton.TabIndex = this.TabIndex;
        radioButton.Enabled = this.Enabled;            
        radioButton.RenderControl(writer);

    }
}

有谁知道我错过了什么？

感谢。

Answer 1

您需要实现IPostBackDataHandler接口并处理几种方法。我给你一些我在类似控件中使用的东西，只是我扩展了单个RadioButton控件而不是列表。我在按钮中添加了自定义Value和GroupName属性，然后在回发时初始化了值。

#region IPostBackDataHandler Members
    void IPostBackDataHandler.RaisePostDataChangedEvent()
    {
        OnCheckedChanged(EventArgs.Empty);
    }

    bool IPostBackDataHandler.LoadPostData(string postDataKey, NameValueCollection postCollection)
    {
        bool result = false;
        //check if a radio button in this button's group was selected
        string value = postCollection[GroupName];
        if ((value != null) && (value == Value)) //was the current radio selected?
        {
            if (!Checked) //select it if not already so
            {
                Checked = true;
                result = true;
            }
        }
        else //nothing or other radio in the group was selected
        {
            if (Checked) //initialize the correct select state
            {
                Checked = false;
            }
        }
        return result;
    }
#endregion

对于未经过优化的代码表示道歉：）

将GroupName添加到RadioButtonList中的项目

1 个答案: