how do I link two Comboboxes together in C#.

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C#

how do I link two Comboboxes together in C# that the two Comboboxes binding to a dataset.

Posted 27-Feb-11 9:41am

saeeddoe

Updated 27-Feb-11 11:47am

Henry Minute

v2

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Henry Minute 27-Feb-11 17:51pm

Without knowing more about what you are trying to do and the structure of your database, it is almost impossible to make any suggestions.

Dave Kreskowiak 27-Feb-11 20:47pm

Define, in functional terms, what you mean by "link"... What do you want to happen? There is no such thing as "linking" control together.

Sunasara Imdadhusen 28-Feb-11 0:30am

Not clear!!

saeeddoe 28-Feb-11 1:36am

I have two table as Requesters and Location. Requesters are some departments like 'Maintenance','HSE','Production'and etc. and each Requester contain some Location. this two tables have relationship one-to-many. it means that for example Maintenance Department have some Location such as 'Maintenance Manager Office','Palanning Office'and etc. and Production Department contain some Location like 'Control Room','Labratory' and etc. so I want first binding this two table to 2 diferent comboboxes and second when I choose one Requester from Requester Combobox, only the Location related to that Requester should be shown in Location Combobox when the form load. I mean this.

Sunasara Imdadhusen 28-Feb-11 2:12am

Now i understand.. i have added answer.

Vivek Krishnamurthy 28-Feb-11 4:25am

Can you please clarify if this a web application ?

2 solutions

Solution 1

I suggest follow these steps

1. Get data from the Requesters table into a dataset
2. Get data from the Location table into the same dataset
3. Create a data relation relating the records in the above tables
4. Create 2 binding source for Requester and Location table and set the datasource of Requester to the dataset and Location to Requester datasource, and datamember of Location to the datarelation created in the step 3.
5. Set the datasource to respective comboboxes.

You can see a detailed example here.

- Vivek

Posted 27-Feb-11 20:24pm

Vivek Krishnamurthy

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Sunasara Imdadhusen · Accepted Answer · 2011-02-27T20:25:00

Hi
First of all you have to fill Requesters drop down your code is like

C#

Page_Load()
{
SQL = "SELECT DISTINCT DepartmentID,Department FROM Requesters"
SQLDataAdapter da = new SQLDataAdapter(SQL, connection);
DataSet ds = new DataSet();
da.Fill(ds);
drpRequesters.DataTextField = "Department";
drpRequesters.DataValueField = "DepartmentID";
drpRequesters.DataSource = ds.Tables[0];
drpRequesters.DataBind();
FillLocation();
}

Now you have to fill Location drop down based on Department selection

C#

private void FillLocation()
{
  if(drpRequesters.SelectedIndex >= 0)
  {
drpLocation.Items.Clear();
    SQL = "SELECT DISTINCT LocationID,Location FROM Locations WHERE DepartmentID=" + drpRequesters.SelectedItem.Value;
SQLDataAdapter da = new SQLDataAdapter(SQL, connection);
DataSet ds = new DataSet();
da.Fill(ds);
drpLocation.DataTextField = "Location";
drpLocation.DataValueField = "LocationID";
drpLocation.DataSource = ds.Tables[0];
drpLocation.DataBind();
  }
}

Final step is you have create change event of Dipartment like

C#

drpDepartment_SelectedIndexChanged()
{
 FillLocation();
}

You should set

XML

AutoPostback="True"

for drpDepartment from .aspx page

Thanks,
Imdadhusen