Asp.net自定义控件之单选、多选控件

Asp.net自定义控件之单选、多选控件

在ASP.NET中，我们可以使用自定义控件来实现复杂的功能和界面。其中单选和多选控件是非常常用的控件，我们可以通过自定义控件的方式来实现它们的功能。

创建自定义控件

我们可以通过继承WebControl类来创建自定义控件。以下是单选、多选控件的基础结构：

public class RadioButtonList : WebControl, INamingContainer
{
    public RadioButtonList()
    {
    }

    protected override void CreateChildControls()
    {
        base.CreateChildControls();

        //创建控件
    }

    protected override void Render(HtmlTextWriter writer)
    {
        //渲染控件
    }
}

public class CheckBoxList : WebControl, INamingContainer
{
    public CheckBoxList()
    {
    }

    protected override void CreateChildControls()
    {
        base.CreateChildControls();

        //创建控件
    }

    protected override void Render(HtmlTextWriter writer)
    {
        //渲染控件
    }
}

创建单选控件示例

下面是一个简单的单选控件示例：

public class RadioButtonList : WebControl, INamingContainer
{
    public RadioButtonList()
    {
    }

    protected override void CreateChildControls()
    {
        base.CreateChildControls();

        for (int i = 0; i < Items.Count; i++)
        {
            RadioButton radioButton = new RadioButton();

            radioButton.ID = string.Format("RadioButton{0}", i);
            radioButton.Text = Items[i].Text;
            radioButton.GroupName = UniqueID;
            radioButton.Attributes.Add("value", Items[i].Value);

            if (SelectedIndex == i)
            {
                radioButton.Checked = true;
            }

            Controls.Add(radioButton);

            LiteralControl space = new LiteralControl(" ");
            Controls.Add(space);
        }
    }

    protected override void Render(HtmlTextWriter writer)
    {
        writer.Write("<div>");

        for (int i = 0; i < Controls.Count; i++)
        {
            Controls[i].RenderControl(writer);
        }

        writer.Write("</div>");
    }

    public ListItemCollection Items
    {
        get
        {
            if (ViewState["Items"] == null)
            {
                ViewState["Items"] = new ListItemCollection();
            }
            return (ListItemCollection)ViewState["Items"];
        }
    }

    public int SelectedIndex
    {
        get
        {
            if (ViewState["SelectedIndex"] == null)
            {
                ViewState["SelectedIndex"] = -1;
            }
            return (int)ViewState["SelectedIndex"];
        }
        set
        {
            ViewState["SelectedIndex"] = value;
        }
    }
}

使用方法：

<cc1:RadioButtonList ID="RadioButtonList1" runat="server">
    <Items>
        <asp:ListItem Text="RadioButton 1" Value="1" />
        <asp:ListItem Text="RadioButton 2" Value="2" />
        <asp:ListItem Text="RadioButton 3" Value="3" />
    </Items>
    <SelectedIndex>1</SelectedIndex>
</cc1:RadioButtonList>

创建多选控件示例

下面是一个简单的多选控件示例：

public class CheckBoxList : WebControl, INamingContainer
{
    public CheckBoxList()
    {
    }

    protected override void CreateChildControls()
    {
        base.CreateChildControls();

        for (int i = 0; i < Items.Count; i++)
        {
            CheckBox checkBox = new CheckBox();
            checkBox.ID = string.Format("CheckBox{0}", i);
            checkBox.Text = Items[i].Text;
            checkBox.Attributes.Add("value", Items[i].Value);

            if (SelectedIndices.Contains(i))
            {
                checkBox.Checked = true;
            }

            Controls.Add(checkBox);

            LiteralControl space = new LiteralControl(" ");
            Controls.Add(space);
        }
    }

    protected override void Render(HtmlTextWriter writer)
    {
        writer.Write("<div>");

        for (int i = 0; i < Controls.Count; i++)
        {
            Controls[i].RenderControl(writer);
        }

        writer.Write("</div>");
    }

    public ListItemCollection Items
    {
        get
        {
            if (ViewState["Items"] == null)
            {
                ViewState["Items"] = new ListItemCollection();
            }
            return (ListItemCollection)ViewState["Items"];
        }
    }

    public List<int> SelectedIndices
    {
        get
        {
            if (ViewState["SelectedIndices"] == null)
            {
                ViewState["SelectedIndices"] = new List<int>();
            }
            return (List<int>)ViewState["SelectedIndices"];
        }
        set
        {
            ViewState["SelectedIndices"] = value;
        }
    }
}

使用方法：

<cc1:CheckBoxList ID="CheckBoxList1" runat="server">
    <Items>
        <asp:ListItem Text="CheckBox 1" Value="1" />
        <asp:ListItem Text="CheckBox 2" Value="2" />
        <asp:ListItem Text="CheckBox 3" Value="3" />
    </Items>
    <SelectedIndices>
        <asp:ListItem Value="1" />
    </SelectedIndices>
</cc1:CheckBoxList>

以上就是单选、多选自定义控件的完整攻略。