Re: Removing duplicates from a DropdownList

[brian richards]

Well I got it to work like this:

public void BindGrid()
{
UpdateSelectStmt();
adptr_LocationSummary.Fill(dsLocationSummary1);
CityChooser.DataSource = dsLocationSummary1;
CityChooser.DataTextField = "City";
CityChooser.DataValueField = "City";
CityChooser.DataBind();
for(int i = 0;i<CityChooser.Items.Count;i++)
{
while( (i+1) < CityChooser.Items.Count && CityChooser.Items.Value ==
CityChooser.Items[i+1].Value)
{
CityChooser.Items.RemoveAt(i+1);
}
}
dg_LocationSummary.DataBind();
}

I wasn't comparing the values before. But this doesn't feel like a very
good solution. Meaning what about when I'm doing this for 8000 cities?

-Brian

 

[Marina]

Why not run a separate query to get the distinct cities? That's really the
way to do it.

Well I got it to work like this:

public void BindGrid()
{
UpdateSelectStmt();
adptr_LocationSummary.Fill(dsLocationSummary1);
CityChooser.DataSource = dsLocationSummary1;
CityChooser.DataTextField = "City";
CityChooser.DataValueField = "City";
CityChooser.DataBind();
for(int i = 0;i<CityChooser.Items.Count;i++)
{
while( (i+1) < CityChooser.Items.Count && CityChooser.Items.Value ==
CityChooser.Items[i+1].Value)
{
CityChooser.Items.RemoveAt(i+1);
}
}
dg_LocationSummary.DataBind();
}

I wasn't comparing the values before. But this doesn't feel like a very
good solution. Meaning what about when I'm doing this for 8000 cities?

-Brian

Brian,

You could filter your initial select statement by using the keyword
DISTINCT.

SELECT DISTINCT citynames FROM tblEntries

If you can't filter the records at the database request level then you can
always build a view in a similar fashion from those records.
Dim DataView As New DataView(dsLocationSummary1.Tables(0))

DataView.RowFilter = "DISTINCT citynames ASC"

CityChooser.DataSource = DataView;
CityChooser.DataTextField = "City";
CityChooser.DataValueField = "City";


Sincerely,

--
S. Justin Gengo, MCP
Web Developer

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www.aboutfortunate.com

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