使用HTML5 FindByValue的DropDownList [英] html5 dropdownlist using FindByValue

问题描述

我的DropDownList HTML5

my dropdownlist HTML5

<select runat="server" id="ddlStateLegalRes" name="ddlStateLegalRes"></select>

在我的网页加载我我的DropDownList绑定到一个列表收集与国家的名单

On my page load I am binding my dropdownlist to a list collection with a list of states

protected void Page_Load(object sender, EventArgs e)
    {

     if (!Page.IsPostBack)
                {
                    List<StateList> states = ops.getStates();
                    ddlStateLegalRes.DataTextField = "StateRegionName";
                    ddlStateLegalRes.DataValueField = "StateRegionCode";
                    ddlStateLegalRes.DataSource = states;
                    ddlStateLegalRes.DataBind();

    GetAllInfo();

EDITED *的 * 的
 有事情很奇怪，我似乎无法找出它，当我调试。由于一些奇怪的原因，这是因为它的工作是应该，但随后开始引发此错误对象引用不设置到对象的实例

EDITED** There is something weird going on and I cant seem to pinpoint it when I debug. For some strange reason this was working as it is supposed to but then started throwing this Error "Object Reference not set to an instance of an object"

我知道名单收集得到正确的价值观，我也知道STATEOFLEGALRESIDENCE是由我的存储过程返回值为FL和拼写是否正确。

I know the list collection is getting the correct values and I also know that "STATEOFLEGALRESIDENCE" is being returned by my stored procedure with the value "FL" and the spelling is correct.

"""Inside my GetAllInfo() method
    while (sdr.Read())
    {
          ddlStateLegalRes.Items.FindByValue(sdr["STATEOFLEGALRESIDENCE"].ToString()).Selected = true;
    }

我怀疑的是，它试图把我的DropDownList与前值实际上是做了code结合我的DropDownList与价值观。所以我试图给GetAllInfo（）方法移动到Page_LoadComplete事件，仍然是同样的错误所以现在我在一个失去了，请帮助

What i suspect is that it is trying to set my dropdownlist with a value before the code is actually done binding my dropdownlist with values. So i tried to move the GetAllInfo() method into the Page_LoadComplete event and still the same error so now I am at a lost please help

感谢

推荐答案

这听起来就像是从阅读器返回的值不完全匹配，或者是从列表项缺失。

It sounds like the value that is returned from the reader does not match exactly or it is missing from the list items.

我把在点与放一个破发点;检查这些值匹配：

I would put a break point at the point & check that these values match:

试试这个，但与该项目的值替换0。

Try this but replace 0 with the value of the item.

 ddlStateLegalRes.Items[0] == sdr["STATEOFLEGALRESIDENCE"].ToString());

这听起来像一个案件或空格triong问题。

It sounds like a case or white space triong issue.

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