How to select the listbox using querystring in c#

Question

I am using c#.

I am trying to select the listbox values from the data coming in querystring. Below is code.

if (!string.IsNullOrEmpty(Security.GetString(Page.Request.Params["VT"])))
        {            
            string[] strCntVisit = Security.GetString(Page.Request.Params["VT"]).Split(',');

            foreach (string i in strCntVisit)
            {
                lstContriesVisited1.SelectedValue = i;

            }                
        }

my problem is that the above code is traversing perfectly, however the issue is that in my listbox my last value of (i) is selected not all the values in querystring.

Please suggest.

Are you saying that you want all values selected from the listbox? — Neil Knight
– Neil Knight, Commented Nov 22, 2010 at 10:50
what u reauired? all values or one one value you selected.Pls specify — kbvishnu
– kbvishnu, Commented Nov 22, 2010 at 10:52
All the values that exists in Page.Request.Params["VT"] to be selected in my first list box — Manoj Singh
– Manoj Singh, Commented Nov 22, 2010 at 10:54

Frédéric Hamidi · Accepted Answer · 2010-11-22 12:28:20Z

3

If your ListBox has its SelectionMode property set to Multiple, you can do:

string vtParam = Security.GetString(Page.Request.Params["VT"]);
if (!String.IsNullOrEmpty(vtParam)) {            
    string[] strCntVisit = vtParam.Split(',');
    foreach (string i in strCntVisit) {
        ListItem item = lstContriesVisited1.Items.FindByValue(i);
        if (item != null) {
            item.Selected = true;
        }
    }                
}

EDIT: The following should answer your comment:

foreach(ListItem item in lstContriesVisited1.Items) {
    lstContriesVisited2.Items.Add(item);
}
lstContriesVisited1.Items.Clear();

edited Nov 22, 2010 at 12:28

answered Nov 22, 2010 at 10:54

Frédéric Hamidi

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1 Comment

Manoj Singh Over a year ago

Thanks Hamidi, one more question, now little change in question, what I want now that I will remove all the items from my first lstContriesVisited1 and will add them to lstContriesVisited2 listbox, please what changes I need to do for this.

Tom · Accepted Answer · 2010-11-22 10:55:25Z

1

SelectedValue is a single item only. Assuming you're using an ASP.NET ListControl, try setting the Selected property on items that match your criteria.

List<string> validItems = new List<string>(strCntVisit);
foreach (ListItem i in lstContriesVisited1.Items) {
    if (validItems.Contains(i.Text)) {
        i.Selected = true;
    }
}

answered Nov 22, 2010 at 10:55

Tom

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Comments

LukeH · Accepted Answer · 2010-11-22 10:57:28Z

0

string vt = Security.GetString(Page.Request.Params["VT"]);
if (!string.IsNullOrEmpty(vt))
{
    string[] valuesToSelect = vt.Split(',');
    foreach (ListItem li in lstContriesVisited1.Items)
    {
        li.Selected = Array.Contains(valuesToSelect, li.Value);
    }
}

(If the VT parameter could potentially contain a lot of values then it might be quicker to change valuesToSelect from an array to a HashSet<T>.)

answered Nov 22, 2010 at 10:57

LukeH

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