Setting ValueMember of combobox

Kevin Fralick

Hi,

I populate a combobox from a recordset of names. I need for the NAME to display but the value to be another column called PERNO. I think I'm supposed to use ValueMember.

Here's my code:

ds = new SqlDataAdapter("select distinct name, perno from empmast order by name", con);

ds.Fill(dt);

for (int i = 0; i < dt.Rows.Count; i++)
   {
      cbOfficer.Items.Add(dt.Rows[i]["name"]);
   }

cbOfficer.DisplayMember = "name";
cbOfficer.ValueMember = "perno";
officer = cbOfficer.ValueMember;

private void btRefresh_Click(object sender, EventArgs e)
{
MessageBox.Show(officer);
}

As you can see, I inserted a MessageBox just to see the value returned. Unfortunately, it is showing the string of "perno" instead of the database value.

I would greatly appreciate your help in showing my mistake. Thank you.

6 Replies

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Vulpes12y ago
Accepted answer
Try:

ds = new SqlDataAdapter("select distinct name, perno from empmast order by name", con);

ds.Fill(dt);

cbOfficer.DataSource = dt; // bind combobox to datatable
cbOfficer.DisplayMember = "name";
cbOfficer.ValueMember = "perno";
cbOfficer.SelectedIndex = 0; // select first item

private void btRefresh_Click(object sender, EventArgs e)
{
MessageBox.Show(cbOfficer.SelectedValue.ToString());
}
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Vulpes12y ago
What we've just done is the recommended (or, at any rate, the usual) way of filling a ListBox or ComboBox with values pulled from a database:

You set the DataSource property to the DataTable or perhaps a DataView and then set the DisplayMember and ValueMember properties to the names of the appropriate columns.

This also works with 'local' arrays or lists of objects.

The only difficulty which can arise in practice is if you want to remove items from or add items to the ComboBox subsequently. You're not allowed to do this directly and so have to make changes to the underlying data source and then rebind.
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Kevin Fralick12y ago
Thank you sir. Unless it's too much trouble, could you show me the more recommended way of doing this?
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Vulpes12y ago
Your main problem, Kevin, was that you were loading the combobox items 'manually' rather than using data-binding. This meant that the combobox had no way of knowing which 'perno' corresponded to a given 'name'.

Setting the DataSource property fixed that and then there was the SelectedValue point which Jasminder drew attention to earlier.
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Kevin Fralick12y ago
You guys are both right. Thank you very much. I guess I was setting the value correctly, just not displaying it right.
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Jasminder Singh12y ago
Isn't there any option combobox.selecteditem or selectedvalue
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