How to generate GridView columns dynamically based on user selection?

How to generate GridView columns dynamically based on user selection?

In case we have to give ability to the user to select the columns that should appear in the GridView, we can follow this approach.

Sometimes due to large number of columns to be displayed on the page in the GridView or give a precise look to the data in GridView, we need to show only those columns in the GridView that is selected by the user. In this article we are going to learn how to dynamically generate GridView columns based on user selection. 

This article has been written based on the question asked in this forum thread.

ASPX Code

<div>


Select column to show in the GridView:<asp:CheckBoxList runat="server" ID="chkFields" DataTextField="Column_name" DataValueField="Column_name" RepeatDirection="Horizontal" RepeatLayout="Flow" />

<p>




<asp:Button ID="btnSub" runat="server" Text="Show" OnClick="ShowGrid" />

</p>
<asp:GridView ID="GridView1" runat="server" EnableViewState="false" AutoGenerateColumns="false" />
</div>

In the above code snippet, we have a CheckBoxList control that lists all the columns of my database table. Apart from this, we have a Show button and a GridView. After selecting the columns from the CheckBoxList control user click on the Show button and accordingly the GridView columns are displayed on the page. Notice that AutoGenerateColumnsproperty is set to false in the GridView.

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Code behind

    string _connStr = ConfigurationManager.ConnectionStrings["ConnStr"].ConnectionString;

protected void Page_Load(object sender, EventArgs e)

{


if (!IsPostBack)

{


BindTableColumns();
}
}

private void BindTableColumns()

{


DataTable table = new DataTable();

using (SqlConnection conn = new SqlConnection(_connStr))

{


using (SqlCommand cmd = new SqlCommand("sp_columns", conn))

{


cmd.CommandType = CommandType.StoredProcedure;

cmd.Parameters.AddWithValue("@table_name", "PersonalDetail");

// get the adapter object and attach the command object to it

using (SqlDataAdapter ad = new SqlDataAdapter(cmd))

{


// fire Fill method to fetch the data and fill into DataTable

ad.Fill(table);
}

chkFields.DataSource = table;

chkFields.DataBind();
}
}
}

private void GetData()

{


DataTable table = new DataTable();

// get the connection

using (SqlConnection conn = new SqlConnection(_connStr))

{


// write the sql statement to execute

string sql = "SELECT AutoId, FirstName, LastName, Age, Active FROM PersonalDetail ORDER By AutoId";

// instantiate the command object to fire

using (SqlCommand cmd = new SqlCommand(sql, conn))

{


// get the adapter object and attach the command object to it

using (SqlDataAdapter ad = new SqlDataAdapter(cmd))

{


// fire Fill method to fetch the data and fill into DataTable

ad.Fill(table);
}
}
}

// specify the data source for the GridView

GridView1.DataSource = table;// bind the data now

GridView1.DataBind();
}



protected void ShowGrid(object sender, EventArgs e)

{


foreach (ListItem item in chkFields.Items)

{


if (item.Selected)

{


BoundField b = new BoundField();

b.DataField = item.Value;

b.HeaderText = item.Value;

GridView1.Columns.Add(b);
}
}

this.GetData();
}