how to create columns dynamically in a grid view

Let�s have a look at the code to understand better.

Create a gridview in the page,

1. Drag and drop the GridView on to the page

Or

1. Manually type GridView definition in the page.

<table border="0" cellpadding="0" cellspacing="0">

            <tr>

                <td>

                    <strong>Dynamic Grid</strong></td>

            </tr>

            <tr>

                <td>

                    <asp:GridView ID="GrdDynamic" runat="server" AutoGenerateColumns="False">

                    <Columns>

                    </Columns>

                    </asp:GridView>

                </td>

            </tr>

        </table>

With this we are done with creating a GridView in the page. Let�s move on to the code- beside to understand the background history of the page.

public partial class _Default : System.Web.UI.Page

{

    #region constants

    const string NAME = "NAME";

    const string ID = "ID";

    #endregion

    protected void Page_Load(object sender, EventArgs e)

    {

        loadDynamicGrid();

    }

    private void loadDynamicGrid()

    {

        #region Code for preparing the DataTable

        //Create an instance of DataTable

        DataTable dt = new DataTable();

        //Create an ID column for adding to the Datatable

        DataColumn dcol = new DataColumn(ID ,typeof(System.Int32));

        dcol.AutoIncrement = true;

        dt.Columns.Add(dcol);

        //Create an ID column for adding to the Datatable

        dcol = new DataColumn(NAME, typeof(System.String));

        dt.Columns.Add(dcol);

        //Now add data for dynamic columns

        //As the first column is auto-increment, we do not have to add any thing.

        //Let's add some data to the second column.

        for (int nIndex = 0; nIndex < 10; nIndex++)

        {

            //Create a new row

            DataRow drow = dt.NewRow();

            //Initialize the row data.

            drow[NAME] = "Row-" + Convert.ToString((nIndex + 1));

            //Add the row to the datatable.

            dt.Rows.Add(drow);

        }

        #endregion

        //Iterate through the columns of the datatable to set the data bound field dynamically.

        foreach (DataColumn col in dt.Columns)

        {

            //Declare the bound field and allocate memory for the bound field.

            BoundField bfield = new BoundField();

            //Initalize the DataField value.

            bfield.DataField = col.ColumnName;

            //Initialize the HeaderText field value.

            bfield.HeaderText = col.ColumnName;

            //Add the newly created bound field to the GridView.

            GrdDynamic.Columns.Add(bfield);

        }

        //Initialize the DataSource

        GrdDynamic.DataSource = dt;

        //Bind the datatable with the GridView.

        GrdDynamic.DataBind();

    }

}

Let�s start dissecting right from the top,

After the page declaration, I have created 2 constants which represent the fields in the outputted grid. After that I am calling the loadDynamicGrid() method which will actually work for you. In this method,

1. Creating a DataTable which will hold the table definition and data for the GridView. This table is used as a DataSource for the GridView
2. Once the DataTable is created, I am creating 2 columns, ID & Name of type integer (ID) and string (Name) and adding them to the DataTable.
3. Since the table structure is ready, I am generating some sample data by iterating through a loop for displaying in the GridView.
4. Now I am iterating through the Columns of the DataTable to create the dynamic columns in the Gridview.
5. The logic behind creating dynamic column starts by creating a BoundField instance.
6. Once the BoundField is created, I am initializing the DataField and HeaderText with the column name of the DataTable.
7. After the BoundField�s basic necessary properties are defined. I am adding the newly created bound field to the GridView control
8. Once the creation of the dynamic columns is completed, I am assigning the DataSource of the GridView and calling the DataBind method to load the GridView with data dynamically.

That�s all your dynamic GridView is ready. I hope this information would be helpful.

In my next article, I will describe about how to create TemplateColumn dynamically. By now, you must have understand how easy is creating BoundColumn. To create any other type of columns like asp:ButtonField, asp:CheckBoxField, asp:CommandField, asp:HyperLinkField, asp:ImageField the logic & strategy is same, except the template column.