Hello Friends,

I've two dropdownlist(ddlCountry,ddlState). Onchange event of CountryDropdown(ddlCountry) StateNames are displayed into StateName dropdown using javascript. And it's working fine but prooblem is if i print the value of selected StateName on a button click at code-behind i got an error Object reference set to an instance of an object. So can anybody let me know what should i do know

Here is my code

This is my javascript function
function myFunc()
{
if(document.getElementById("ddlCountry").value=="I ndia")
{
//Remove Existing Values
var e=document.getElementById("ddlState");
while(e.firstChild)
{
e.removeChild(e.firstChild);
}
var myArray=new Array(2);
myArray[0]="Delhi";
myArray[1]="Mumbai";


for(var i=0;i<myArray.length;i++)
{
//Option(Text,Value)
e.options[i]=new Option(myArray[i]);
}

}
else if(document.getElementById("ddlCountry").value=="A merica")
{
//Remove Existing Values
var e=document.getElementById("ddlState");
while(e.firstChild)
{
e.removeChild(e.firstChild);
}

var myArray=new Array(2);
myArray[0]="Washington";
myArray[1]="LA";


for(var i=0;i<myArray.length;i++)
{
//Option(Text,Value)
e.options[i]=new Option(myArray[i]);
}
}

}

This is my .aspx code
<asp:DropDownList ID="ddlCountry" runat="server" onchange="myFunc(this)">
<asp:ListItem Text="Select Country" Value="Select Country"></asp:ListItem>
<asp:ListItem Text="India" Value="India"></asp:ListItem>
<asp:ListItem Text="America" Value="America"></asp:ListItem>
</asp:DropDownList>
<asp:DropDownList ID="ddlState" runat="server">
</asp:DropDownList>

This is my Code-Behind(on button click event) code
string name = ddlCountry.SelectedItem.Text+","+ddlState.Selected Item.Text;
Label1.Text = name.ToString();

And ddlState.SelectedItem.Text getting null that's why that's throwing error

You are populating the ddlState control, but that doesn't mean there is a selected item there. There is no "default" selected item when a dropdownlist is first populated. An item must be explicitly selected (either on the client or programmatically) for SelectedItem to have a non-null value.

You probably should consider using validation to force the user to make a selection in ddlState before the postback.

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