javascript-当下拉索引selectedIndex相同时,不会触发__doPostBack()
作者：互联网
我有两个下拉菜单ddlCountry和ddlState和一个按钮Submit.
当ddlstate在更新面板中时.
在提交两个下拉按钮的值时,将它们存储在数据库中.
然后在Repeater Control中显示数据.(以HTML Table结构)
ASPX代码
<table id="tablelist" class="csstablelist" cellspacing="1" cellpadding="1">
<tr>
<td class="csstablelisttoptr">
ddlCountryID
</td>
<td class="csstablelisttoptr">
ddlCountryText
</td>
<td class="csstablelisttoptr">
ddlstateText
</td>
</tr>
<asp:Repeater ID="repeaterList" runat="server" OnItemDataBound="repeaterList_ItemDataBound">
<ItemTemplate>
<tr onclick="selectRow(this);">
<td class="csstablelisttd" style="display: none">
<asp:Label ID="ddlCountryID" runat="server" Text='<%#Eval("ddlCountryID")%>'></asp:Label>
</td>
<td class="csstablelisttd">
<asp:Label ID="ddlCountryText" runat="server" Text='<%#Eval("ddlCountryText")%>'></asp:Label>
</td>
<td class="csstablelisttd">
<asp:Label ID="ddlstateText" runat="server" Text='<%#Eval("ddlstateText")%>'></asp:Label>
</td>
</tr>
</ItemTemplate>
</asp:Repeater>
</table>
<asp:DropDownList ID="ddlCountry" runat="server" CssClass="csstextbox" Width="207px" AutoPostBack="true" OnSelectedIndexChanged="ddlCountry_SelectedIndexChanged">
</asp:DropDownList>
<asp:UpdatePanel ID="updatePanelState" runat="server">
<ContentTemplate>
<asp:DropDownList ID="ddlState " runat="server" CssClass="csstextbox" Width="177px">
</asp:DropDownList>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="ddlCountry" EventName="SelectedIndexChanged" />
</Triggers>
</asp:UpdatePanel>
<asp:Button ID="btnSave" runat="server" Width="80px" OnClientClick="return validateForm();" Text="Save" CssClass="cssbutton" OnClick="btnSave_Click" />
ddlCountryID | ddlCountryText | ddlstateText
1 | USA | XYZ
2 |India | PQR
TR的Onclick我在javascript中编写了(SelectRow(this))函数,以突出显示转发器值和下拉值匹配并被选中.
<script type="text/javascript">
function selectRow(objTR)
{
var ddlCountry =document.getElementById('<%=ddlCountry.ClientID %>');
var ddlState =document.getElementById('<%=ddlState .ClientID %>');
for (i = 0; i < ddlCountry .options.length; i++)
{
if (ddlCountry .options[i].text == objTR.cells[1].innerText.trim())
break;
}
ddlCountry .options[i].selected = true;
__doPostBack(ddlCountry .id, objTR.cells[2].innerText.trim());
}
</script>
我在代码后面写了ddlCountry SelectedIndexChangedEvent.
从Java语言中,我正在触发__doPostBack()并将ddlCountry作为事件目标ddlStateText作为事件参数传递给SelectedIndexChangedEvent,并在这样的事件中获取值.
string stateDescription = Request["__EVENTARGUMENT"];
ddlState .Items.FindByText(stateDescription ).Selected = true;//for highliting the repeater value and dropdown value match and selected
在页面上绑定国家
if(!Ispostback)
protected Void BindCountry()
{
strSQL = @"SELECT countryID,Country from Country_Master";
DataTable dataTableCountry = null;
dataTableCountry = objSqlDbComm.ExecuteDatasetQuery(strSQL).Tables[0];
int countryID;
string Country;
var dictioneryCountry = new Dictionary<int, string>();
foreach(DataRow dr in dataTableCountry.Rows)
{
countryID = Convert.ToInt32(dr["countryID"]);
Country= dr["Country"].ToString();
dictioneryCountry.Add(countryID,Country);
}
ddlCountry.Items.Clear();
ddlCountry.DataTextField = "Value";
ddlCountry.DataValueField = "Key";
ddlCountry.DataSource = dictioneryCountry;
ddlCountry.DataBind();
ddlCountry.Items.Insert(0, new ListItem("[Select]", "-1"));
ddlCountry.Items[0].Selected = true;
}
我的问题是,如果我有以下中继器数据.
ddlCountryID | ddlCountryText | ddlstateText
1 | USA | XYZ
2 |India | PQR
2 |India | MNO
当我选择具有国家印度和州mno的行号3时,__ dopostback()方法将启动.
当我转到第1行时,则__dopostback()方法启动.
当我从第1行到第3行时,方法是正确的射击方式,但是当从第3行到第2行具有国家ID相同的__dopostback()方法时,则不启动,并且未从ddlstate中选择状态.
解决方法:
如果调试代码,则会看到__doPostBack()确实在工作,因为正在执行Page_Load中的代码(尝试在此处设置断点以进行检查).问题是DropDownList的索引没有更改,因此不会触发IndexChanged事件,并且ddlCountry_SelectedIndexChanged永远不会运行.当您调用__doPostBack()时,这与从背后的代码中手动调用ddlCountry_SelectedIndexChanged不同.
除了设置此下拉列表值之外,您是否有其他原因需要回发？
解决方案1
我建议删除__doPostBack()行并添加以下内容：
var state = objTR.cells[2].innerText.trim();
for (var i = 0; i < ddlState.options.length; i++)
{
if (ddlState.options[i].text == state)
{
ddlState.options[i].selected = true;
break;
}
}
解决方案2
另外,如果您确实需要发回邮件,则可以执行以下操作：
一种.在更新面板中添加一个隐藏按钮,如下所示：
<div style="display: none">
<asp:Button ID="btnState" OnClick="btnState_Click" runat="server" />
</div>
b.选择国家/地区后,将您的JavaScript更改为执行以下操作：
document.getElementById('__EVENTARGUMENT').value = objTR.cells[2].innerText.trim();
document.getElementById('<%= btnState.ClientID %>').click();
C.创建一个FilterState()函数并从您的ddlcountry indexchanged事件中调用它
protected void ddlCountry_SelectedIndexChanged(object sender, EventArgs e)
{
FilterState();
}
private void FilterState()
{
// insert whatever filtering code you had here
}
d.添加您的btnState_Click函数(请注意,如果您之前已设置了ddlState的选定项,则如果已选择该项,则会抛出错误.)：
protected void btnState_Click(object sender, EventArgs e)
{
FilterState();
string state = Request["__EVENTARGUMENT"];
if (state != "")
ddlState.SelectedValue = state;
}
解决方案3
第三种解决方案将允许您仍然使用__doPostBack,并将此事件放入Page_Load函数中,从而完全废弃SelectedIndexChanged事件：
if (IsPostBack && Request["__EVENTTARGET"] == ddlCountry.UniqueID)
{
FilterState();
string stateDescription = Request["__EVENTARGUMENT"];
if (stateDescription != "")
ddlState.SelectedValue = stateDescription;
}
另外,对于BindCountry函数,没有使用字典的真正理由,您可以直接绑定DataTable：
strSQL = @"SELECT countryID,Country from Country_Master";
DataTable dataTableCountry = objSqlDbComm.ExecuteDatasetQuery(strSQL).Tables[0];
ddlCountry.Items.Clear();
ddlCountry.DataSource = dataTableCountry;
ddlCountry.DataTextField = "Country";
ddlCountry.DataValueField = "countryID";
ddlCountry.DataBind();
ddlCountry.Items.Insert(0, new ListItem("[Select]", "-1"));
ddlCountry.Items[0].Selected = true;
标签：c-4-0,dopostback,asp-net,javascript 来源： https://codeday.me/bug/20191201/2079551.html