Two related listBoxes question

  • Thread starter Thread starter Guy Dillen
  • Start date Start date
G

Guy Dillen

I want to relate 2 listBoxes. Although during the filling of the first
listBox1; the event SelectedIndexChanged already fires (this is not the
purpose). The event should only fire when a select an item in listBox1.
How can i avoid that the event fires too early?


....
private void button3_Click(object sender, System.EventArgs e)
{

DataSet ds = new DataSet();

DataAdapter da = null;

string SQLcom = "SELECT toto, id FROM table";

da = new DataAdapter(SQLcom, conn);

da.Fill(ds, "table");

listBox1.DataSource = ds.Tables["table"];

listBox1.ValueMember = "id";

listBox1.DisplayMember = "toto";

listBox1.SelectedIndex = -1;

}

private void listBox1_SelectedIndexChanged(object sender, System.EventArgs
e)

{

DataSet ds = new DataSet();

DataAdapter da = null;

string SQLcom = "SELECT tata, id FROM table2";

da = new DataAdapter(SQLcom, conn);

da.Fill(ds, "table2");

listBox2.DataSource = ds.Tables["table2"];

listBox2.ValueMember = "id";

listBox2.DisplayMember = "tata";

listBox2.SelectedIndex = -1;

}
 
Turn of the eventhandler during loading and add it back
when done,

listBox1.SelectedIndexChanged -= new
EventHandler(listBox1_SelectedIndexChanged)
....
listBox1.SelectedIndexChanged += new
EventHandler(listBox1_SelectedIndexChanged)

or use a flag that you check at the beginning
of listBox1_SelectedIndexChanged


/claes
 
Ok thx for the info.

I suppose this is the correct way to achive this (=relating/linking 2
listBoxes)? Or is this way not the correct one?

Guy



Claes Bergefall said:
Turn of the eventhandler during loading and add it back
when done,

listBox1.SelectedIndexChanged -= new
EventHandler(listBox1_SelectedIndexChanged)
...
listBox1.SelectedIndexChanged += new
EventHandler(listBox1_SelectedIndexChanged)

or use a flag that you check at the beginning
of listBox1_SelectedIndexChanged


/claes

Guy Dillen said:
I want to relate 2 listBoxes. Although during the filling of the first
listBox1; the event SelectedIndexChanged already fires (this is not the
purpose). The event should only fire when a select an item in listBox1.
How can i avoid that the event fires too early?


...
private void button3_Click(object sender, System.EventArgs e)
{

DataSet ds = new DataSet();

DataAdapter da = null;

string SQLcom = "SELECT toto, id FROM table";

da = new DataAdapter(SQLcom, conn);

da.Fill(ds, "table");

listBox1.DataSource = ds.Tables["table"];

listBox1.ValueMember = "id";

listBox1.DisplayMember = "toto";

listBox1.SelectedIndex = -1;

}

private void listBox1_SelectedIndexChanged(object sender,
System.EventArgs
e)

{

DataSet ds = new DataSet();

DataAdapter da = null;

string SQLcom = "SELECT tata, id FROM table2";

da = new DataAdapter(SQLcom, conn);

da.Fill(ds, "table2");

listBox2.DataSource = ds.Tables["table2"];

listBox2.ValueMember = "id";

listBox2.DisplayMember = "tata";

listBox2.SelectedIndex = -1;

}
Click to expand...
Click to expand...
 
Thanks for your help, it works.

One more question:
is this the correct way to achive this (realting/linking listBoxes)? Or are
there other more used methods to achieve this?

Guy


Claes Bergefall said:
Turn of the eventhandler during loading and add it back
when done,

listBox1.SelectedIndexChanged -= new
EventHandler(listBox1_SelectedIndexChanged)
...
listBox1.SelectedIndexChanged += new
EventHandler(listBox1_SelectedIndexChanged)

or use a flag that you check at the beginning
of listBox1_SelectedIndexChanged


/claes

Guy Dillen said:
I want to relate 2 listBoxes. Although during the filling of the first
listBox1; the event SelectedIndexChanged already fires (this is not the
purpose). The event should only fire when a select an item in listBox1.
How can i avoid that the event fires too early?


...
private void button3_Click(object sender, System.EventArgs e)
{

DataSet ds = new DataSet();

DataAdapter da = null;

string SQLcom = "SELECT toto, id FROM table";

da = new DataAdapter(SQLcom, conn);

da.Fill(ds, "table");

listBox1.DataSource = ds.Tables["table"];

listBox1.ValueMember = "id";

listBox1.DisplayMember = "toto";

listBox1.SelectedIndex = -1;

}

private void listBox1_SelectedIndexChanged(object sender,
System.EventArgs
e)

{

DataSet ds = new DataSet();

DataAdapter da = null;

string SQLcom = "SELECT tata, id FROM table2";

da = new DataAdapter(SQLcom, conn);

da.Fill(ds, "table2");

listBox2.DataSource = ds.Tables["table2"];

listBox2.ValueMember = "id";

listBox2.DisplayMember = "tata";

listBox2.SelectedIndex = -1;

}
Click to expand...
Click to expand...
 
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