CODEWITHSUNDEEP
c#datatabledataset
guest86
guest86

Reputation: 2956

How to check if DataTable contains DataRow?

I have a non-typed dataset filled with data from user input (no database). There's no primary key column (my data had no need for primary key so far)! Is there any way to avoid "brute force" if i want to check if new row user is trying to insert already exists in my DataTable? How should i perform that check?

Upvotes: 0

Views: 12364

Answers (4)

Carlos ABS
Carlos ABS

Reputation: 723

Much, much easier way:

datatable.Columns.Contais("ColumnName")

Upvotes: -1

Cᴏʀʏ
Cᴏʀʏ

Reputation: 107498

You can manually create unique constraints for your DataTable:

DataTable custTable = custDS.Tables["Customers"];
UniqueConstraint custUnique = new UniqueConstraint(new DataColumn[] 
    {custTable.Columns["CustomerID"], 
    custTable.Columns["CompanyName"]});
custDS.Tables["Customers"].Constraints.Add(custUnique);

For this example, you would get an exception (of type ConstraintException) if you tried to add a row to the table where the CustomerID and CompanyName were duplicates of another row with the same CustomerID and CompanyName.

I would just let the DataTable check these things for you internally - no point reinventing the wheel. As to how it does it (whether it is efficient or not), will have to be an exercise for you.

Upvotes: 2

Glory Raj
Glory Raj

Reputation: 17691

To check for any duplicates try

if (table.Rows.Contain(PriKeyTypeValue)) /*See if a Primary Key Value is in 
the table already */
    continue;
else
    table.Row.Add(value1, value2, value3);

If you want to be able to insert duplicate rows but do not want to have an exception thrown set-up your primary key as a unique self-incrementing int then you can insert as many duplicates as you feel like without having to check to see if the table contains that value.you can set primary key value like the below.... 

DataTable table = new DataTable();

table.Columns.Add("Column", typeof(int));

DataColumn column = table.Columns["Column"];
column.Unique = true;
column.AutoIncrement = true;
column.AutoIncrementStep = 1; //change these to whatever works for you
column.AutoIncrementSeed = 1;
table.PrimaryKey = new DataColumn[] { column };

Upvotes: 0

Haedrian
Haedrian

Reputation: 4328

What you can do is use a DataView. Dataview allow you to use a where clause with the DataView's data.

Check it that way.

Upvotes: 0

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