本文介绍了DropDownList的选定值没有改变？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
DropDownList的选择值不发生变化。虽然字符串_month也含有的价值，但DropDownList的是没有得到it.all其他都工作正常，但只有ddlMonth.selected值不changing.i已指定_month价值，但它不改变，为什么？只有ddlMonth是不会改变所有其它的原因ddlmonth是不会改变工作正常？
如果（_objMonth.Contains（月））
{
字符串_Month =（字符串）_objMonth.GetData（月）;
ddlMonth.SelectedValue = _Month;
///这里ddlMonth.selected价值没有得到来自_month新的价值
}
其他code低于
保护无效的Page_Load（对象发件人，发送System.EventArgs）
{
如果（Page.IsPostBack）
返回;
尝试
{
负载（）;
GetYears（）;
如果（！string.IsNullOrEmpty（ddlYear.SelectedValue））
hYearId.Value = ddlYear.SelectedValue;
GetPeriods（Convert.ToInt32（hYearId.Value））;
GetDepartment（）;
GetSection（）; ＃地区都被选择登录用户部门和部分
ddldepartment.SelectedValue = CommonMethods.UserContext.EmployeeDeparmentID;
ddlSection.SelectedValue = CommonMethods.UserContext.EmployeeSectionID; #endregion ddldepartment_SelectedIndexChanged（NULL，NULL）;
ddlemp_SelectedIndexChanged（NULL，NULL）;
字符串名称=的Request.QueryString [ID]作为字符串; ＃地区创建Cache对象 的ICacheManager _objYear = CacheFactory.GetCacheManager（）; //创建缓存对象
的ICacheManager _objMonth = CacheFactory.GetCacheManager（）; //创建缓存对象
的ICacheManager _objDepartment = CacheFactory.GetCacheManager（）; //创建缓存对象
的ICacheManager _objSection = CacheFactory.GetCacheManager（）; //创建缓存对象
#endregion 如果（的Request.QueryString [ClickTag会]！= NULL）
{
＃区域设置缓存的项目
如果（的Request.QueryString [ClickTag会]。的ToString（）==1）
{
如果（_objYear.Contains（年））
{
字符串_Year =（字符串）_objYear.GetData（年）;
ddlYear.SelectedValue = _Year;
}
如果（_objMonth.Contains（月））
{
字符串_Month =（字符串）_objMonth.GetData（月）;
ddlMonth.SelectedValue = _Month;
}
如果（_objDepartment.Contains（部））
{
字符串_Department =（字符串）_objDepartment.GetData（部）;
ddldepartment.SelectedValue = _Department;
}
如果（_objSection.Contains（科））
{
字符串_Section =（字符串）_objSection.GetData（科）;
ddlSection.SelectedValue = _Section;
}
}
#endregion
}保护无效ddlMonth_SelectedIndexChanged（对象发件人，EventArgs的发送）
{
尝试
{
如果（！string.IsNullOrEmpty（ddlMonth.SelectedValue））
{
hClpid.Value = ddlMonth.SelectedValue.Split（，）[0];
会话[开始日期] = ddlMonth.SelectedValue.Split（，）[2];
会话[结束日期] = ddlMonth.SelectedValue.Split（，）[3];
ddldepartment_SelectedIndexChanged（NULL，NULL）;
ddlemp_SelectedIndexChanged（NULL，NULL）;
如果（ddlSection.SelectedIndex大于0）
ddlSection_SelectedIndexChanged（NULL，NULL）;
}
}无效GetPeriods（INT _year）
{
IBLCalenderPeriod _bl =（IBLCalenderPeriod）SetupBLFactory.GetCalenderPeriod（）; 数据集_ds =（数据集）_bl.GetPeriodIdsByYear（_year）.GetMaster（）; _ds.Tables [0] .Columns.Add（ID）; 的foreach（在_ds.Tables的DataRow _dr [0] .Rows）
{
_dr [ID] = _dr [CLP_ID] +，+ _dr [clp_activeperiod] +，+ _dr [CLP_DATESTART] +，+ _dr [CLP_DATEEND] +; }
ddlMonth.DataSource = _ds.Tables [0];
ddlMonth.DataTextField =CLP_DESCRIPTION;
ddlMonth.DataValueField =ID;
ddlMonth.DataBind（）; 的foreach（在_ds.Tables的DataRow _dr [0] .Rows）
{
如果（_dr [clp_activeperiod]！= NULL）
如果（_dr [clp_activeperiod]。的ToString（）==1）
{
ddlMonth.SelectedValue = _dr [ID]的ToString（）。
hClpid.Value = ddlMonth.SelectedValue.Split（，）[0];
会话[开始日期] = ddlMonth.SelectedValue.Split（，）[2];
会话[结束日期] = ddlMonth.SelectedValue.Split（，）[3];
打破;
}
其他
{
ddlMonth.SelectedIndex = 0;
hClpid.Value =0;
}
}
}
解决方案
我觉得你在设置，但ddlMonth一个ddlMonth值不具有绑定值..尝试值设置为之前绑定在你的ddlMonth值列表它
dropdownlist selected value is not changing. although the string _month also contain the value but dropdownlist is not getting it.all other are working fine but only ddlMonth.selected value is not changing.i have assigned _month value to it but its not changing why? only ddlMonth is not changing all other are working fine why ddlmonth is not changing?
if (_objMonth.Contains("Month"))
{
string _Month = (string)_objMonth.GetData("Month");
ddlMonth.SelectedValue = _Month;
///here ddlMonth.selected value is not getting new value from _month
}
Other code is below
protected void Page_Load(object sender, System.EventArgs e)
{
if (Page.IsPostBack)
return;
try
{
OnLoad();
GetYears();
if (!string.IsNullOrEmpty(ddlYear.SelectedValue))
hYearId.Value = ddlYear.SelectedValue;
GetPeriods(Convert.ToInt32(hYearId.Value));
GetDepartment();
GetSection();
#region Get Selected login user department and section
ddldepartment.SelectedValue = CommonMethods.UserContext.EmployeeDeparmentID;
ddlSection.SelectedValue = CommonMethods.UserContext.EmployeeSectionID;
#endregion
ddldepartment_SelectedIndexChanged(null, null);
ddlemp_SelectedIndexChanged(null, null);
string name = Request.QueryString["id"] as string;
#region Create Cache object
ICacheManager _objYear = CacheFactory.GetCacheManager();//Create cache object
ICacheManager _objMonth = CacheFactory.GetCacheManager();//Create cache object
ICacheManager _objDepartment = CacheFactory.GetCacheManager();//Create cache object
ICacheManager _objSection = CacheFactory.GetCacheManager();//Create cache object
#endregion
if (Request.QueryString["ClickTag"]!=null)
{
#region set Cached items
if (Request.QueryString["ClickTag"].ToString() == "1")
{
if (_objYear.Contains("Year"))
{
string _Year = (string)_objYear.GetData("Year");
ddlYear.SelectedValue = _Year;
}
if (_objMonth.Contains("Month"))
{
string _Month = (string)_objMonth.GetData("Month");
ddlMonth.SelectedValue= _Month;
}
if (_objDepartment.Contains("Department"))
{
string _Department = (string)_objDepartment.GetData("Department");
ddldepartment.SelectedValue= _Department;
}
if (_objSection.Contains("Section"))
{
string _Section = (string)_objSection.GetData("Section");
ddlSection.SelectedValue = _Section;
}
}
#endregion
}
protected void ddlMonth_SelectedIndexChanged(object sender, EventArgs e)
{
try
{
if (!string.IsNullOrEmpty(ddlMonth.SelectedValue))
{
hClpid.Value = ddlMonth.SelectedValue.Split(',')[0];
Session["Startdate"] = ddlMonth.SelectedValue.Split(',')[2];
Session["EndDate"] = ddlMonth.SelectedValue.Split(',')[3];
ddldepartment_SelectedIndexChanged(null, null);
ddlemp_SelectedIndexChanged(null, null);
if (ddlSection.SelectedIndex > 0)
ddlSection_SelectedIndexChanged(null, null);
}
}
void GetPeriods(int _year)
{
IBLCalenderPeriod _bl = (IBLCalenderPeriod)SetupBLFactory.GetCalenderPeriod();
DataSet _ds = (DataSet)_bl.GetPeriodIdsByYear(_year).GetMaster();
_ds.Tables[0].Columns.Add("ID");
foreach (DataRow _dr in _ds.Tables[0].Rows)
{
_dr["ID"] = _dr["CLP_ID"] + "," + _dr["clp_activeperiod"] + "," + _dr["CLP_DATESTART"] + "," + _dr["CLP_DATEEND"] + "";
}
ddlMonth.DataSource = _ds.Tables[0];
ddlMonth.DataTextField = "CLP_DESCRIPTION";
ddlMonth.DataValueField = "ID";
ddlMonth.DataBind();
foreach (DataRow _dr in _ds.Tables[0].Rows)
{
if (_dr["clp_activeperiod"] != null)
if (_dr["clp_activeperiod"].ToString() == "1")
{
ddlMonth.SelectedValue = _dr["ID"].ToString();
hClpid.Value = ddlMonth.SelectedValue.Split(',')[0];
Session["Startdate"] = ddlMonth.SelectedValue.Split(',')[2];
Session["EndDate"] = ddlMonth.SelectedValue.Split(',')[3];
break;
}
else
{
ddlMonth.SelectedIndex = 0;
hClpid.Value = "0";
}
}
}
解决方案
I think you are setting a value in ddlMonth but ddlMonth do not have that binded value.. Try to bind list of values in your ddlMonth before setting a value to it
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