.Net Tips , C# Tips : Concatenate or Combine LINQ query Results or DataSources with C# Examples and VB.Net Examples

There is a situations where you want to Concatenate Or Combine one or more data sources using  LINQ.
With the help of the Concat<> extension method to concatenate or combine multiple sources into a single data source.

Here is example of this.
In this example we execute two different LINQ Query on DataTable and find two different results object. After that we concatenate in one datasource and display.

C# Examples :

        DataSet ds = new DataSet();
        DataTable dt = new DataTable();
        DataColumn dc;
        DataRow dr;
        ds.DataSetName = "products";
        dt.TableName = "product";

        dc = new DataColumn("product_id", long.MaxValue.GetType());
        dt.Columns.Add(dc);

        dc = new DataColumn("product_name");
        dt.Columns.Add(dc);

        dr = dt.NewRow();
        dr["product_id"] = 1;
        dr["product_name"] = "Monitor";
        dt.Rows.Add(dr);

        dr = dt.NewRow();
        dr["product_id"] = 2;
        dr["product_name"] = "Mouse";
        dt.Rows.Add(dr);

        dr = dt.NewRow();
        dr["product_id"] = 3;
        dr["product_name"] = "KeyBoard";
        dt.Rows.Add(dr);

        dr = dt.NewRow();
        dr["product_id"] = 4;
        dr["product_name"] = "LCD";
        dt.Rows.Add(dr);

        ds.Tables.Add(dt);

        IEnumerable<DataRow> objResult1 = from tbl in dt.AsEnumerable()
                                          where tbl.Field<long>(0) >= 3
                                          select tbl;

        Response.Write("<b>Query Results 1</b>");
        foreach (DataRow row in objResult1)
        {
            Response.Write(string.Format("<br/>Product ID: {0} ,  Product Name: {1}", row.Field<long>(0), row.Field<string>(1)));
        }

        IEnumerable<DataRow> objResult2 = from tbl in ds.Tables[0].AsEnumerable()
                                          let product_name = tbl.Field<string>(1)
                                          where product_name.StartsWith("Key")
                                          || product_name.StartsWith("Mo")
                                          select tbl;

        Response.Write("<br/><br/><b>Query Results 2</b>");
        foreach (DataRow row in objResult2)
        {
            Response.Write(string.Format("<br/>Product ID: {0} ,  Product Name: {1}", row.Field<long>(0), row.Field<string>(1)));
        }


        IEnumerable<DataRow> objConcatenateResult = objResult1.Concat(objResult2);

        Response.Write("<br/><br/><b>Concatenate Or Combine Query Results</b>");
        foreach (DataRow row in objConcatenateResult)
        {
            Response.Write(string.Format("<br/>Product ID: {0} ,  Product Name: {1}", row.Field<long>(0), row.Field<string>(1)));
        }

VB.net Examples :

        Dim ds As New DataSet()
        Dim dt As New DataTable()
        Dim dc As DataColumn
        Dim dr As DataRow
        ds.DataSetName = "products"
        dt.TableName = "product"

        dc = New DataColumn("product_id", Long.MaxValue.GetType())
        dt.Columns.Add(dc)

        dc = New DataColumn("product_name")
        dt.Columns.Add(dc)

        dr = dt.NewRow()
        dr("product_id") = 1
        dr("product_name") = "Monitor"
        dt.Rows.Add(dr)

        dr = dt.NewRow()
        dr("product_id") = 2
        dr("product_name") = "Mouse"
        dt.Rows.Add(dr)

        dr = dt.NewRow()
        dr("product_id") = 3
        dr("product_name") = "KeyBoard"
        dt.Rows.Add(dr)

        dr = dt.NewRow()
        dr("product_id") = 4
        dr("product_name") = "LCD"
        dt.Rows.Add(dr)

        ds.Tables.Add(dt)

        Dim objResult1 As IEnumerable(Of DataRow) = From tbl In dt.AsEnumerable()
                                      Where tbl.Field(Of Long)(0) >= 3
                                      Select tbl

        Response.Write("<b>Query Results 1</b>")
        For Each row As DataRow In objResult1
            Response.Write(String.Format("<br/>Product ID: {0} ,  Product Name: {1}", row.Field(Of Long)(0), row.Field(Of String)(1)))
        Next

        Dim objResult2 As IEnumerable(Of DataRow) = From tbl In ds.Tables(0).AsEnumerable()
                                    Let product_name = tbl.Field(Of String)(1)
                                    Where product_name.StartsWith("Key") Or product_name.StartsWith("Mo")
                                    Select tbl

        Response.Write("<br/><br/><b>Query Results 2</b>")
        For Each row As DataRow In objResult2
            Response.Write(String.Format("<br/>Product ID: {0} ,  Product Name: {1}", row.Field(Of Long)(0), row.Field(Of String)(1)))
        Next

        Dim objConcatenateResult As IEnumerable(Of DataRow) = objResult1.Concat(objResult2)

        Response.Write("<br/><br/><b>Concatenate Or Combine Query Results</b>")
        For Each row As DataRow In objConcatenateResult
            Response.Write(String.Format("<br/>Product ID: {0} ,  Product Name: {1}", row.Field(Of Long)(0), row.Field(Of String)(1)))
        Next

Output : 

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