Solved

adding blank row to datasource

Posted on 2010-08-30
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Last Modified: 2012-05-10
Hi,

I am populating combobox from two tables with following query

private void Fillcmbbankerid()
        {
            try
            {
                {
                    prefetchPathbanker.Add(BankerEntity.PrefetchPathBank);
                    bucketbanker.PredicateExpression.Add(BankerFields.Flag ==
                                                         StandardFlag.recordvalidflag);
                    adapterbanker.FetchEntityCollection(datasourcebanker, bucketbanker, 0,
                                                        new SortExpression(BankerFields.BankerId |
                                                                           SortOperator.Ascending),
                                                        prefetchPathbanker);
                    cmbbankerid.DataSource = datasourcebanker;
                    cmbbankerid.DisplayMember = "DESCRIPTION";
                    cmbbankerid.ValueMember = "BANKERID";
                    cmbbankerid.SelectedIndex = -1;
                }
            }
            catch (Exception ex)
            {
                GlobalErrorHandler.LogMessage(ex.Message + ex.StackTrace);
            }
            finally
            {
                adapterbanker.CloseConnection();
            }
        }

Output of query what I have written is SELECT   BANK.DESCRIPTION, BANKER.BANKER_ID
  FROM   BANKER, BANK
 WHERE   (BANK.BANK_ID = BANKER.BANK_ID) AND (BANKER.FLAG = 0)

Problem
Now the question is how to i add a blank row to this datasource. ?
Remember, I am using two tables here
0
Comment
Question by:GRChandrashekar
  • 8
  • 5
14 Comments
 
LVL 53

Expert Comment

by:Dhaest
Comment Utility
Do you want an empty item added to the combobox or what exactly do you want ?

http://www.tek-tips.com/faqs.cfm?fid=5281
0
 

Author Comment

by:GRChandrashekar
Comment Utility
Well I know how to add an empty Item

The problem is adding an empty item when I am loading combobox with relations from 2 tables as stated in my query under my question.
0
 
LVL 9

Expert Comment

by:puru1981
Comment Utility
it is possible to do but you need to use union for this. where you can write a select query which will return a single blank row.

but its better to use it this way because it will be scalable.

you can use combobox insertAt method to add an empty item because from the select query it would be not possible.
0
 

Author Comment

by:GRChandrashekar
Comment Utility
Would you please explain this

insertAt method
0
 
LVL 9

Expert Comment

by:puru1981
Comment Utility
sorry it is Insert Method
 
cmbbankerid.Items.Insert(0, "None");
        cmbbankerid.Items.Insert(datasourcebanker.Length, "All");
0
 

Author Comment

by:GRChandrashekar
Comment Utility
This line does not work
datasourcebanker.Length
0
 
LVL 9

Expert Comment

by:puru1981
Comment Utility
i don't know the datatype of datasourcebanker so i written that. basic purpose was to insert the index. i thought it was an array so used Length. you can use appropriately.
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Author Comment

by:GRChandrashekar
Comment Utility
it is basically datasource which am using like  cmbbankerid.DataSource = datasourcebanker;

Not sure what i have to select instead of length
0
 

Author Comment

by:GRChandrashekar
Comment Utility
I get option       datasourcebanker(int index,object item)

So what to write ?
0
 
LVL 9

Accepted Solution

by:
puru1981 earned 500 total points
Comment Utility
just remove this line. i have used it to insert a row at the end of the combobox.

alternatively, provide me the datatype of datasourcebanker.
0
 

Author Comment

by:GRChandrashekar
Comment Utility
datasource banker is just an entity collection
0
 

Author Comment

by:GRChandrashekar
Comment Utility
which am using like
private readonly EntityCollection datasourcebanker =
            new EntityCollection(new BankerEntityFactory());
0
 
LVL 9

Expert Comment

by:puru1981
Comment Utility
you can use count property for this.
0
 

Author Comment

by:GRChandrashekar
Comment Utility
How ? I just need to add an empty row with index 0
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