Datatable/Datarow If Exists Update Else Insert

Question

Trying to find an answer to this has proven difficult, since all the answers deal with SQL! I have a Datatable `TestTable`. In this DataTable I have three columns, `ID`, `ValueX`, and `ValueY`. As I add new records to this datatable, I am trying to make an insert method that looks to see if the record exists, but cannot get a Select statement to use multiple fields. In my situation, I need to see if the Datatable contains a record that equals ID and ValueX, if it does, update. Otherwise, add the new record to the datatable. ``` public void Insert(string ID, string ValueX, string ValueY) { DataRow dr = TestTable.NewRow(); dr["ID"] = ID; dr["ValueX"] = ValueX dr["ValueY"] = ValueY; TestTable.Rows.Add(dr); } ```

Accepted Answer

You can use the `Find` method

DataRowCollection.Find Method (Object[])

Gets the row that contains the specified primary key values.

to look for a specific `DataRow`. Note that your `DataTable` has to have a appropriate primary key.

Example:

```
// create Table with ID, ValueX, ValueY
var table1 = new DataTable();
var id = table1.Columns.Add("ID");
var x = table1.Columns.Add("ValueX");
var y = table1.Columns.Add("ValueY");

// set primary key constain so we can search for specific rows
table1.PrimaryKey = new[] {id, x};

// some sample data
table1.Rows.Add(new Object[] {1, 1, 100});
table1.Rows.Add(new Object[] {2, 2, 200});

// find the row with key {1, 1} and update it, if it exists
// else you would want to create a new row
var exisiting = table1.Rows.Find(new Object[] {1, 1});
if (exisiting != null)
    exisiting.ItemArray = new object[] {1, 1, 9999};
```

Datatable/Datarow If Exists Update Else Insert

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