使用SqlDataAdapter.Update方法时复制表行

Question

In my project I have table "Product".

ID  Name   Price
------------------  
1   xyz     100

2   abc     200

3   pqr     300

In my c# code I would like to update my table rows using SqlAdapter. For that i crated a datatable

DataTable dtTable=new DataTable("Product");

Add updated values to Datatable .That is,

ID  Name   Price
    ------------------  
    1   aaa     100

    2   bbb     200

    3   ccc     300

I used the following step to update table in database with this values

SqlConnection myLocalConnection = new SqlConnection(_ConnectionString);
SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter("Select * from " + dtTable.TableName, myLocalConnection);
 SqlCommandBuilder mySqlCommandBuilder = new SqlCommandBuilder(mySqlDataAdapter);

     mySqlDataAdapter.Update(dtTable);

But when executing this update function, In database all tables are duplicated. that is

ID  Name   Price
------------------  
1   xyz     100

2   abc     200

3   pqr     300

4   aaa     100

5   bbb     200

6   ccc     300

I only want to replace the existing data. Why these rows are duplicated in this table. Please help

Answer 1

According to Updating Data Sources with DataAdapters you have to specify your update command by yourself and then you can call the Update function of the sql data adapter!

SqlDataAdapter mySqlDataAdapter = 
     new SqlDataAdapter("Select * from " + dtTable.TableName, myLocalConnection);
dataAdpater.UpdateCommand = new SqlCommand("UPDATE ...", connection);
mySqlDataAdapter.Update(dtTable);