asked on

Assign datatable from DataSet

I want to assign a datatable to another datatable (create from a datasoruces)

Dim mdtPO As New OrderTrackingDataSet.OrderMasterDataTable '<--- data table created by datasources
cnn.Open()
mDA = New System.Data.OleDb.OleDbDataAdapter("Select * from " & mTableName, mCnn)
mDA.Fill(mDS, mTableName)
mCB = New System.Data.OleDb.OleDbCommandBuilder(mDA)
mdtPO = mDS.Tables(mTableName)
cnn.Close()

However I got the following error message !
"Unable to cast object of type 'System.Data.DataTable' to type 'OrderMasterDataTable'."

So how can I assign datatable "mDS.Tables(mTableName)" to mdtPO ?

Thanks in advance!

Arthur_Wood

try this:

Dim mdtPO As New OrderTrackingDataSet.OrderMasterDataTable '<--- data table created by datasources
cnn.Open()
mDA = New System.Data.OleDb.OleDbDataAdapter("Select * from " & mTableName, mCnn)
mDA.Fill(mDS, mTableName)
mCB = New System.Data.OleDb.OleDbCommandBuilder(mDA)
mdtPO = cType( mDS.Tables(mTableName), OrderTrackingDataSet.OrderMasterDataTable)
cnn.Close()

AW

tora111

ASKER

Arthur_Wood,

It got the same error "Unable to cast object of type 'System.Data.DataTable' to type 'OrderMasterDataTable'."

It seems cannot assign to a datataboe to a datatable(from data sources, xsd) directly !!!

LordWabbit

I would guess that 'OrderMasterDataTable' is a class which inherits from a datatable with some methods thrown in for fun and profit. You might need to add the records one at a time.

Bob Learned

How is mDS declared and set?

Bob

tora111

ASKER

OrderTrackingDataSet a xsd is created by data sources

mDS is a dataset

Bob Learned

mDs should be OrderTrackingDataSet, and not just plain ol' DataSet.

Bob

tora111

ASKER

Bob, it doesn't a matter! My objective is to allow add/change/delete the "OrderTrackingDataSet.OrderMasterDataTable" by coding.

Is it possible to use coding method to manipulate a xsd datatable ?

Bob Learned

It does matter if you are trying to cast a DataTable from the strong type DataSet into a strong type.

Bob

tora111

ASKER

I see, in other words, is it possible to manipulate a datatable from a strong type dataset by coding method ? Because I don't know how to ...., could you give me some example for it !

ASKER CERTIFIED SOLUTION

Bob Learned

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tora111

ASKER

Thanks Bob, I'm wonder if we can use tableadapter and bindingsource to manipulate the strong type dataset table then it'll be more simple.

But I don't how to change the database source (for example a mdb file), I don't want to hard code the database because sometimes we need to deploy to different location and mdb file!!!