Bind NameValueCollection to GridView?

Question

What kind of collection I should use to convert NameValue collection to be bindable to GridView? When doing directly it didn't work.

Code in aspx.cs

  private void BindList(NameValueCollection nvpList)
  {
     resultGV.DataSource = list;
     resultGV.DataBind();
  }

Code in aspx

<asp:GridView ID="resultGV" runat="server" AutoGenerateColumns="False" Width="100%">
    <Columns>
         <asp:BoundField DataField="Key" HeaderText="Key" />
         <asp:BoundField DataField="Value" HeaderText="Value" />
    </Columns>
</asp:GridView>

Any tip most welcome. Thanks. X.

Solution 1

Can you use Dictionary<string,string> instead of NameValueCollection. Since Dictionary<T,T> implements IEnumerable you could use LINQ as so:

resultGV.DataSource = from item in nvpDictionary
                      select new { Key = item.Key, Value = item.Value };
resultGV.DataBind();

[EDIT] Actually you may be able to use Dictionary directly as:

resultGV.DataSource = nvpDictionary;
resultGV.DataBind();

If it doesn't map key/value the way you want you can always go back to LINQ. LINQ would also allow you to rename the fields to whatever you want.

[EDIT] If you can't change to use Dictionary<T,T>, make a copy of the NameValueCollection as a Dictionary in the method and bind to it.

private void BindList(NameValueCollection nvpList)
{
   Dictionary<string,string> temp = new Dictionary<string,string>();
   foreach (string key in nvpList)
   {
      temp.Add(key,nvpList[key]);
   }

   resultGV.DataSource = temp;
   resultGV.DataBind();
}

If you do this a lot, you could write an extension method to convert to a Dictionary, and use it so.

public static class NameValueCollectionExtensions
{
   public static Dictionary<string,string> ToDictionary( this NameValueCollection collection )
   {
      Dictionary<string,string> temp = new Dictionary<string,string>();
      foreach (string key in collection)
      {
          temp.Add(key,collection[key]);
      }
      return temp;
   }
}

private void BindList(NameValueCollection nvpList)
{
   resultGV.DataSource = nvpList.ToDictionary();
   resultGV.DataBind();
}

Solution 2

It's a little tricky, because the enumerator returns only the Keys. But, you can get the Key value with Container.DataItem, and then look up into the NameValueCollection to get the value:

<asp:GridView id="gv" runat="server" AutoGenerateColumns="false">
   <Columns>
      <asp:TemplateField HeaderText="Key">
         <ItemTemplate><%# Container.DataItem %></ItemTemplate>
      </asp:TemplateField>
      <asp:TemplateField HeaderText="Value">
         <ItemTemplate>
            <%# ((NameValueCollection)gv.DataSource)[(string)Container.DataItem] %>
         </ItemTemplate>
      </asp:TemplateField>
   </Columns>
</asp:GridView>

Solution 3

Finally I used solution suggested in your extension implementation, but without extension itself.

  private void BindList(NvpList nvpList)
  {
     IDictionary dict = new Dictionary<string, string>();

     foreach (String s in nvpList.AllKeys)
        dict.Add(s, nvpList[s]);

     resultGV.DataSource = dict;
     resultGV.DataBind();
  }

maybe do some helper class that will be static and do the translation for me in one place instead of many. This extension is quite handy... :-)

Thanks. X.

Solution 4

I find it best to use a StringDictionary for databinding & accessing key & value

Dim sDict as New StringDictionary
sDict.Add("1","data1")
sDict.Add("2","data2")
sDict.Add("3","data3")
...

CheckBoxList1.DataSource = sDict
CheckBoxList1.DataValueField = "key"
CheckBoxList1.DataTextField = "value"
CheckBoxList1.DataBind()

Solution 5

If you have a nested Repeater (or GridView too, I'm sure), you need to alter Mark Brackett's answer to look like this, or else you'll get a run-time error about not being able to find a control with the name of rpt.

<asp:Repeater ID="rpt" runat="server">
<ItemTemplate>
    <li>
        <%# Container.DataItem %>:
        <%# ((NameValueCollection)((Repeater)Container.Parent).DataSource)[(string)Container.DataItem] %>
    </li>    
</ItemTemplate>
</asp:Repeater>

View more solutions

Comments

[Jaroslav Urban]

I can't change it to Dictionary as it's ext object and I am still using Net 2.0. But thanks...anyway. Every opinion helps.

[ChocoMartin]

See my answer for a necessary change if you are using a nested DataBound Repeater-like control with NameValueCollection

[magnattic]

Keep in mind though that NameValueCollection can have duplicate keys, while Dictionary does not. So you could run into trouble/lose information when converting to a Dictionary.