绑定DROPDOWNLIST与OPTGROUP从SQL数据源 [英] Bind Dropdownlist with optGroup from sql datasource

问题描述

我要绑定应该按区域分组六国的一个DropDownList，我发现了一个样本code从下面的链接，

I have to bind a Dropdownlist with coutries which should be grouped by region, I have found a sample code from the following link,

<一个href=\"http://www.$c$cproject.com/KB/custom-controls/DropDownListOptionGroup.aspx?msg=3984074#xx3984074xx\" rel=\"nofollow\">http://www.$c$cproject.com/KB/custom-controls/DropDownListOptionGroup.aspx?msg=3984074#xx3984074xx

我想要的国家列表与此相同。但问题是，我想从SQL结果DropDownList的绑定。我曾尝试以下，但没有工作，

I wanted the country list same as this. But problem is that I want to bind the dropdownlist from sql result. I have tried the following but didn't work,

ddlCountry.DataSource = CountryDtoCollection;
ddlCountry.DataBind();
ddlCountry.Attributes.Add("OptionGroup", "Region");

任何人知道这个任何解决方案。

any one knows any solution for this.

推荐答案

您可以编写一个自定义服务器控件和使用含有分隔文本和区域中的数据源女巫的 | ，然后把它分解时使用

you can write a custom server control and use the data source witch containing the text and region separated by | then split it when use.

[ToolboxData("<{0}:CustomDropDownList runat=server></{0}:CustomDropDownList>")]
public class CustomDropDownList : DropDownList
{
    protected override void RenderContents(HtmlTextWriter writer)
    {
        if (this.Items.Count > 0)
        {
            bool selected = false;
            bool optGroupStarted = false;
            string lastOptionGroup = string.Empty;
            for (int i = 0; i < this.Items.Count; i++)
            {
                ListItem item = this.Items[i];
                if (item.Enabled)
                {
                    if (lastOptionGroup != item.Text.Split("|")[1])
                    {
                        if (optGroupStarted)
                        {
                            writer.WriteEndTag("optgroup");
                        }
                        lastOptionGroup = item.Text.Split("|")[1];
                        writer.WriteBeginTag("optgroup");
                        writer.WriteAttribute("label", lastOptionGroup);
                        writer.Write('>');
                        writer.WriteLine();
                        optGroupStarted = true;
                    }
                    writer.WriteBeginTag("option");
                    if (item.Selected)
                    {
                        if (selected)
                        {
                            this.VerifyMultiSelect();
                        }
                        selected = true;
                        writer.WriteAttribute("selected", "selected");
                    }
                    writer.WriteAttribute("value", item.Value, true);
                    if (item.Attributes.Count > 0)
                    {
                        item.Attributes.Render(writer);
                    }
                    if (this.Page != null)
                    {
                        this.Page.ClientScript.RegisterForEventValidation(this.UniqueID, item.Value);
                    }
                    writer.Write('>');
                    HttpUtility.HtmlEncode(item.Text.Split("|")[0], writer);
                    writer.WriteEndTag("option");
                    writer.WriteLine();
                }
            }
            if (optGroupStarted)
            {
                writer.WriteEndTag("optgroup");
            }

        }
    }
}

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