CODEWITHSUNDEEP
c#linqdrop-down-menu
Si8
Si8

Reputation: 9225

How to use LINQ with DropDownList

I have two dropdownlist:

<asp:DropDownList ID="dropdownlist1" runat="server">
    <asp:ListItem>Select One</asp:ListItem>
    <asp:ListItem>once</asp:ListItem>
    <asp:ListItem>twice</asp:ListItem>
    <asp:ListItem>thrice</asp:ListItem>
</asp:DropDownList>

<asp:DropDownList ID="dropdownlist2" runat="server">
    <asp:ListItem>Select One</asp:ListItem>
    <asp:ListItem>1/22/2014</asp:ListItem>
    <asp:ListItem>1/25/2016</asp:ListItem>
</asp:DropDownList>

How can I set up LINQ to do the following:

I did the following:

GridView1.DataSource = List1
    .Where(en => 
        en.howManyTimes == (dropdownlist1.SelectedIndex > 0 ? dropdownlist1.SelectedItem.Value : ""))
    .Select(en => new { en.TheID, en.GetFile, en.GetLink });

I am just not sure after the : in the ternary operator.

This is what I would like:

GridView1.DataSource = List1.Where(en => en.howManyTimes == (if dropdownlist1 selected index is great than 0 then use that value for howManyTimes, otherwise select any howManyTimes) && en.whatDate == (if dropdownlist2 selected index is great than 0 then use that value for whatDate, otherwise select any whatDate)).Select(en => new { en.TheID, en.GetFile, en.GetLink });

Can I please get some assistance in completing it.

Upvotes: 1

Views: 75

Answers (1)

Gert Arnold
Gert Arnold

Reputation: 109119

If Any of the selected index is greater than 0 then use the condition otherwise select all.

You can achieve this by making the predicate evaluate to something that's always true when dropdownlist1.SelectedIndex <= 0:

GridView1.DataSource = List1
    .Where(en => dropdownlist1.SelectedIndex <= 0
              || en.howManyTimes == dropdownlist1.SelectedItem.Value)
    .Select(en => new { en.TheID, en.GetFile, en.GetLink });

Upvotes: 1

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