Copy from one datatable to another datatable ..

santosh parida

12y24.2k.NET

I have two data table .

I want to copy first 10 records of my first datatable to another datatable ... columns are coming dynamic so we cant mention the column name.

8 Replies

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SUNIL GUTTA12y ago
yes vulpes ur absolutely spot on .. i guess better to use while which is faster ?? else foreach (altough performance is same just for its advantages)

datatable dt =new datatable();
dt ----- > fill this
DataTable dt1 = dt.Clone();
foreach(DataRow dr in dt.Rows)
{
dt1.Rows.Add(dr.ItemArray);

}
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Vulpes12y ago
Well, if you're going to copy some of the rows (no matter how many) from one DataTable to another, then I don't see what choice you have but to use a loop.

The DataTable.Copy method copies all the rows but doesn't have an overload which copies only a subset of them. If you were copying nearly all the rows, then it might be quicker to copy all of them and then remove the ones you don't want.

Do you really need to copy the rows at all? Couldn't you just operate from the original DataTable?
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santosh parida12y ago
Thnx for the answer. But in my application i m supposed to take more than 10,000 rows in the datatable..if i am going to use for loop then the performance will be decreased as the loop is going to execute for 10,000 times.
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Vulpes12y ago
Even if it is a big DataTable, I don't see why you can't use a for loop to select the first 'n' DataRows. Just try it and see if performance is acceptable.

To copy the top 50 records, change this line:

int max = Math.Min(10, dt.Rows.Count);

to this:

int max = Math.Min(50, dt.Rows.Count);

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santosh parida12y ago
hi Vulpes thnx for your answer.
But unfortunately i have a large database. so i can't use for loop.

For example Can we copy top 50 records to another datatable from first datatable.
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Sanjay Kumar12y ago
HI

http://support.microsoft.com/default.aspx?scid=kb;EN-US;Q308909

http://stackoverflow.com/questions/4020270/copy-rows-from-datatable-to-another-datatable-c-sharp
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Vulpes12y ago
If the second DataTable is a clone of the first one (i.e. it has the same columns in the same order), then you should be able to do it with this code:

DataTable dt2 = dt.Clone(); // if needed
int max = Math.Min(10, dt.Rows.Count);
for(int i = 0; i < max; i++)
{
DataRow dr = dt2.NewRow();
dr.ItemArray = dt.Rows[i].ItemArray;
dt2.Rows.Add(dr);
}
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Sunny Sharma12y ago
Hi Santosh,

In relational Database, there's no concept for inserting the values without column name unless you have all the values matching to al the column in an order. You have to have the names.
Although it's coming dynamically, you need to get the column name from what it's coming and the insert the columns accordingly.

Share your code what you've tried so far or where you're stuck?
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