[英]how to write javascript validation for dropdown selected index changed event in c#
I have a dropdown.Basing on this dropdown i shud load another dropdown.i wrote code in on selected index changed event in .cs page.Depending on selectd item in first dropdown i need to give a validation in javascript.let us think i should show an alert.Can any one help me out. 我有一个下拉列表。我基于此下拉列表加载另一个下拉列表。我在.cs页面的选定索引更改事件中编写了代码。根据第一个下拉列表中的选定项目,我需要在javascript中进行验证。让我们认为我应该显示警报。任何人都可以帮助我。
in .aspx page 在.aspx页面中
<asp:DropDownList ID="drpdes" runat="server" onselectedindexchanged="drpdes_SelectedIndexChanged"></asp:DropDownList>
in .cs page 在.cs页面中
protected void Page_Load(object sender, EventArgs e)
{
drpdes.AutoPostBack = true;
}
protected void drpdes_SelectedIndexChanged(object sender, EventArgs e)
{
int flgchk = 0;
if(drpdes.selectedvalue == "0")
{
flgchk = 1;
}
// my code for binding second dropdown
}
when flgchk = 1 i need to show an alert from javascript.i wrote a function for alert in javascript.But i am not understanding where to call it. 当flgchk = 1时,我需要显示一个来自javascript的警报。我在javascript中编写了一个警报功能,但我不知道在哪里调用它。
something like this :) 像这样的东西:)
protected void drpdes_SelectedIndexChanged(object sender, EventArgs e)
{
int flgchk = 0;
if(drpdes.selectedvalue == "0")
{
flgchk = 1;
/// this will call your alert method.
string errorScript = "<script type=\"text/javascript\">" +
"YourFunctionNameHere() " +
"</script>";
ClientScript.RegisterClientScriptBlock(this.GetType(), "alert", errorScript);
}
// my code for binding second dropdown
}
If you remove AutoPostback on your dropdownlist you can validate client side. 如果您在下拉列表中删除自动回发,则可以验证客户端。 Something like onchange = YourJSMethod(this.value).
诸如onchange = YourJSMethod(this.value)之类的东西。
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