我有ddlCountry dropdownlist和ddlState下拉列表 . ddlState位于更新面板中 . 在选择国家时,我使用ddlCountry的selectedindexchanged事件填充了其状态 . 我在绑定后的两个下拉列表中都添加了起始值“-1”,如果下拉列表内容为[Select]值“-1”,则检入Javascript然后提醒并返回false .
但验证适用于ddlCountry,对于ddlState,在ajax更新面板触发并验证失败后,其值变为“空白” .
我该如何解决?我不知道为什么在AsyncPostBackTrigger之后ddlState值丢失了 .
//javascript validation
function validateForm()
{
if (ddlCountry .value == "-1")
{
alert("Country should not be blank.");
ddlCountry .focus();
return false;
}
if (ddlState .value == "-1")
{
alert("State should not be blank.");
ddlState .focus();
return false;
}
return true;
}
//Aspx code
<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>
//Code Behind
protected void Page_Load(object sender, EventArgs e)
{
if(!IsPostBack)
{
BindCountry();
}
}
protected void ddlCountry_SelectedIndexChanged(object sender, EventArgs e)
{
int countryID = Convert.ToInt32(ddlCountry.SelectedItem.Value);
ifcountryID == -1)
{
return;
}
strSQL = @"SELECT State_ID,State_Desc
FROM State_Master
WHERE countryID = '" + countryID + @"';
DataTable dataTableState = null;
dataTableState = objSqlDbComm.ExecuteDatasetQuery(strSQL).Tables[0];
var dictioneryState = new Dictionary<int, string>();
foreach(DataRow dr in dataTableStudy.Rows)
{
dictioneryState .Add(Convert.ToInt32(dr["State_ID"]), dr["State_Desc"].ToString());
}
ddlState.DataTextField = "Value";
ddlState.DataValueField = "Key";
ddlState.DataSource = dictioneryState;
ddlState.DataBind();
ddlState.Items.Insert(0, new ListItem("[Select]", "-1"));
ddlState.Items[0].Selected = true;
}
1 回答
对于两个下拉列表,将viewstate设置为true,如下所示:
它可能会解决您的问题 .
谢谢