What does If Not String.IsNullOrEmpty means

Question

User945338570 posted

hi,

Can you please explain me what is the meaning of "If Not String.IsNullOrEmpty(ddl_userid.SelectedValue) Then" where it is exactly used?

Answer 1

User-2139489267 posted

If Not String.IsNullOrEmpty(ddl_userid.SelectedValue)

That means value is not null or not an empty string.

where it is exactly used?

When you want to check above criteria.

Answer 2

User-1716253493 posted

See this dropdownlist

    <asp:DropDownList ID="ddl_userid" runat="server">
        <asp:ListItem Value="">No Body</asp:ListItem>
        <asp:ListItem Value="Me">Me</asp:ListItem>
        <asp:ListItem Value="You">You</asp:ListItem>
    </asp:DropDownList>

First value is Empty String

Your code checking if you select any item that has value (item 1 "Me" or item 2 "You") then do something

Your code will not be executed if you select first item BLANK VALUE

Answer 3

User-1360095595 posted

http://msdn.microsoft.com/en-us/library/system.string.isnullorempty.aspx

For something basic like this you should get used to using Google/Bing.