CODEWITHSUNDEEP
vb.netdatatable
SmileAshis
SmileAshis

Reputation: 113

Compare between two datatables and merge into new datatable

Suppose i have two data table contain same column name, But record may or may not be the same. My question is how to compare between two data table and marge into new one. example:

datatable 1

Name     value
A           1
B           2
C           3   
D           4

datatable 2

Name    value
A        9
B        2
D        1

New datatable(Compare based on datatable 1)

Name    value(From1)   value(From2)
A             1            9
B             2            2
C             3 
D             4            1

If a record present in datatable1 is not present in datatable2 then add blank. Here the datatable generate from XML. I am using vb.net 2008 express.

Upvotes: 1

Views: 10707

Answers (2)

sloth
sloth

Reputation: 101072

Create a primary key on the Name column. Then make sure the value columns have different names (like value1 and value2). Then simply use Merge():

Example:

Dim dt1 = New DataTable()
dt1.Columns.Add("Name", GetType(String))
dt1.Columns.Add("value1", GetType(Integer))
dt1.Rows.Add({"A", 1})
dt1.Rows.Add({"B", 2})
dt1.Rows.Add({"C", 3})
dt1.Rows.Add({"D", 4})
dt1.PrimaryKey = {dt1.Columns("Name")}

Dim dt2 = New DataTable()
dt2.Columns.Add("Name", GetType(String))
dt2.Columns.Add("value2", GetType(Integer))
dt2.Rows.Add({"A", 9})
dt2.Rows.Add({"B", 2})
dt2.Rows.Add({"D", 1})
dt2.PrimaryKey = {dt2.Columns("Name")}

dt1.Merge(dt2)

dt1 now looks like:

enter image description here

Upvotes: 3

Pragnesh Khalas
Pragnesh Khalas

Reputation: 2898

I Think below code will help you

    'dtTable1 - First Table
    'dtTable2 - Secound Table
    'dtNewData - Result Table

    Dim dtNewData As New DataTable
    dtNewData = dtTable1.Copy()
    dtNewData.PrimaryKey = New DataColumn() {dtNewData.Columns("Name")}
    dtNewData.Columns.Add("Value2")
    For Each dr As DataRow In dtTable2.Rows
        If dtNewData.Rows.Contains(dr("Name")) = False Then
            Dim dr1 As DataRow = dtNewData.NewRow
            dr1("Name") = dr("Name")
            dr1("Value2") = dr("Value")
            dtNewData.Rows.Add(dr1)
        Else
            dtNewData.Rows.Find(dr("Name"))("Value2") = dr("Value")
        End If
    Next

Upvotes: 1

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