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Merge Two Datatable Columns and Bind to ComboBox Control

Posted by Santhosh Kumar Jayaraman Articles | Windows Forms C# July 28, 2012
In this article, let us see how to bind a combobox with various columns from various datatables.
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Introduction

In this article, let us see how to bind a ComboBox with various columns from various datatables.

For example, I have a datatable "Server" with columns "server" and "database". Another datatable "server1" with columns "servername" and "databasename". Now I want to display all the values in the server and servername columns into a single ComboBox.

Using the code

  1. Create a new Windows application. Add a ComboBox control.
  2. I have 2 XML files to dump into datasets:

    XML File 1

    <?xml version="1.0" standalone="yes" ?>
    -<NewDataSet>
    -<Table1>
     <Server>Server1</Server>
     <Database>Database1</Database>
     </Table1>
    -<Table1>
     <Server>Server2</Server>
     <Database>Database2</Database>
     </Table1>
    -<Table1>
     <Server>Server3</Server>
     <Database>Database3</Database>
     </Table1>
     </NewDataSet>

    XML File 2

    <?xml version="1.0" standalone="yes" ?>
    -<NewDataSet>
    -<table2>
     <ServerName>Server4</ServerName>
     <DatabaseName>Database4</DatabaseName>
     </table2>
    -<table2>
     <ServerName>Server5</ServerName>
     <DatabaseName>Database5</DatabaseName>
     </table2>
    -<table2>
     <ServerName>Server6</ServerName>
     <DatabaseName>Database6</DatabaseName>
     </table2>
    </
    NewDataSet>
     

  3. Now in the form_load, add the following code. I am going to merge 2 datatables from 2 datasets. Then going to create a new column in the merged dataset and fill the new column with values from both datatables. See the commented lines for more explanation and a better understanding.

    privatevoid Form1_Load(object sender, EventArgs e)
    {

       DataSet ds = newDataSet();

       string path = "C:\\XMLFile1.xml";

        //Read XMLFILE1.XML and save it in ds

        ds.ReadXml(path);

        path ="C:\\XMLFile2.xml";

       DataSet ds2 = new DataSet();

        //Read XMLFILE2.XML and save it in ds2

        ds2.ReadXml(path);

        //Merge datatable from both datasets

        ds.Tables[0].Merge(ds2.Tables[0]);

        //add new column "All Servers"

        ds.Tables[0].Columns.Add("All Servers", typeof(string));

        //Read datatable and fetch all server and dump it into new column "All servers"

    foreach (DataRow dr in ds.Tables[0].Rows)

    {

        dr["All Servers"] = dr["server"].ToString();

    }

    //Read datatable and fetch all servername and dump it into new column "All servers"

    foreach (DataRow dr in ds.Tables[0].Rows)

    {

        //When we merged 2 datatables if there are 3 rows in datatable 1 and 2 in datatable2

    //now it will become 5rows,So am checking if its blank, then fill it with servername column from datatable2(initial)

       if (dr["All Servers"] == "")

            dr["All Servers"] = dr["servername"].ToString();

    }

    //Bind the datatable

    comboBox1.DataSource = ds.Tables[0];

    //set displaymember as "All servers", the newly created column.

                comboBox1.DisplayMember = "All Servers";

    }

     

  4. Now run the application and check the ComboBox; you will have all the servers listed inside the ComboBox:

    Datatable.jpg


I have attached the complete source code also.

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