BoundColumn.DataFormatString Property


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Gets or sets the string that specifies the display format for items in the column.

Namespace:   System.Web.UI.WebControls
Assembly:  System.Web (in System.Web.dll)

public virtual string DataFormatString { get; set; }

Property Value

Type: System.String

A formatting string that specifies the display format of items in the column. The default value is String.Empty.

Use the DataFormatString property to provide a custom format for the items in the column.

The data format string consists of two parts, separated by a colon, in the form { A : Bxx }. For example, the formatting string {0:F2} displays a fixed-point number with two decimal places.


The entire string must be enclosed in braces to indicate that it is a format string and not a literal string. Any text outside the braces is displayed as literal text.

The value before the colon (A in the general example) specifies the parameter index in a zero-based list of parameters.


This value can only be set to 0 because there is only one value in each cell.

The character after the colon (B in the general example) specifies the format to display the value in. The following table lists the common formats.

Format character



Displays numeric values in currency format.


Displays numeric values in decimal format.


Displays numeric values in scientific (exponential) format.


Displays numeric values in fixed format.


Displays numeric values in general format.


Displays numeric values in number format.


Displays numeric values in hexadecimal format.


The format character is not case-sensitive, except for X, which displays the hexadecimal characters in the case specified.

The value after the format character (xx in the general example) specifies the number of significant digits or decimal places to display.

For more information on formatting strings, see Formatting Types in the .NET Framework.

The following example demonstrates how to use the DataFormatString property to specify various formats for the columns in the DataGrid control. The Qty column is formatted as an integer, the Price column is formatted as currency, the Weight column is formatted as a decimal number, and the Expires column is formatted as a short date and time string.

<%@ Page language="c#" AutoEventWireup="true" %>
<%@ Import Namespace="System.Data" %>
<%@ Import Namespace="System.Globalization" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
<html xmlns="" >
    <head runat="server">
        <title>BoundColumn Example</title>
       <script runat="server">
        // The Cart and CartView objects temporarily store the data source
        // for the DataGrid control while the page is being processed.
        DataTable Cart;
        DataView CartView;   

        void Page_Load(Object sender, EventArgs e) 
            // With a database, use a select query to retrieve the data. 
            // Because the data source in this example is an in-memory 
            // DataTable, retrieve the data from session state if it exists; 
            // otherwise, create the data source.

            // The DataGrid control maintains state between posts to the 
            // server; therefore it only needs to be bound to a data source 
            // the first time the page is loaded or when the data source 
            // is updated.
            if (!IsPostBack)

        void ItemsGrid_Edit(Object sender, DataGridCommandEventArgs e) 
            // Set the EditItemIndex property to the index of the item 
            // clicked in the DataGrid control to enable editing for that
            // item. Be sure to rebind the DateGrid to the data source 
            // to refresh the control.
            ItemsGrid.EditItemIndex = e.Item.ItemIndex;

        void ItemsGrid_Cancel(Object sender, DataGridCommandEventArgs e) 
            // Set the EditItemIndex property to -1 to exit editing mode.  
            // Be sure to rebind the DateGrid to the data source to 
            // refresh the control.
            ItemsGrid.EditItemIndex = -1;

        void ItemsGrid_Update(Object sender, DataGridCommandEventArgs e) 
            // Retrieve the updated values.
            // For bound columns, the edited value is stored in a TextBox.
            // The TextBox is the 0th control in a cell's Controls collection.
            // Each cell in the Cells collection of a DataGrid item represents
            // a column in the DataGrid control.
            DataGridItem updateItem = e.Item;

            TextBox qtyText = (TextBox)updateItem.Cells[2].Controls[0];
            TextBox priceText = (TextBox)updateItem.Cells[3].Controls[0];

            try {
                // Try to parse the updated values from the input text.
                Int32 newQty;
                Decimal newPrice;

                newQty = Int32.Parse(qtyText.Text, NumberStyles.Number);
                newPrice = Decimal.Parse(priceText.Text, NumberStyles.Currency);

                // Get the item cell value - "Item 1", "Item 2", etc.
                // For read-only columns, the value is stored in the cell text.
                String item = updateItem.Cells[1].Text;

                // With a database, use an update command to update the data. 
                // Because the data source in this example is an in-memory
                // DataTable, delete the old row and replace it with a new one.

                // Filter on the updated item, remove it,
                // then clear the row filter.
                CartView.RowFilter = "Item='" + item + "'";
                if (CartView.Count > 0)
                CartView.RowFilter = "";

                // Add the updated entry for the item.
                DataRow dr = Cart.NewRow();
                dr["Item"] = item;
                dr["Qty"] = newQty;
                dr["Price"] = newPrice;
                dr["Weight"] = updateItem.Cells[4].Text;
                dr["Expires"] = updateItem.Cells[5].Text;

            catch (System.FormatException)
                // If parsing the price or quantity caused an 
                // exception, then leave edit mode without
                // changing any cell values.

            // Set the EditItemIndex property to -1 to exit editing mode.  
            // Be sure to rebind the DataGrid to the data source to refresh
            // the control.
            ItemsGrid.EditItemIndex = -1;

        void BindGrid() 
            // Set the data source and bind to the Data Grid control.
            ItemsGrid.DataSource = CartView;

        void GetSource()
            // For this example, the data source is a DataTable that is 
            // stored in session state.
            // If the data source does not exist, create it; otherwise, 
            // load the data.

            if (Session["ShoppingCart"] == null) 
                Cart = new DataTable();
                // Retrieve the sample data from session state.
                Cart = (DataTable)Session["ShoppingCart"];

            // Create a DataView and specify the field to sort by.
            CartView = new DataView(Cart);


        void InitSource()
            // Create the sample data.

            // Define the columns of the table.
            Cart.Columns.Add(new DataColumn("Qty", typeof(Int32)));
            Cart.Columns.Add(new DataColumn("Item", typeof(String)));
            Cart.Columns.Add(new DataColumn("Price", typeof(Decimal)));
            Cart.Columns.Add(new DataColumn("Weight", typeof(Decimal)));
            Cart.Columns.Add(new DataColumn("Expires", typeof(DateTime)));

            // Store the table in session state to persist its values 
            // between posts to the server.
            Session["ShoppingCart"] = Cart;

            // Populate the DataTable with sample data.
            DataRow dr;  

            for (int i = 1; i <= 4; i++) 
                dr = Cart.NewRow();
                dr["Qty"] = i % 2 + 1;
                dr["Item"] = "Item " + i.ToString();
                dr["Price"] = (0.50 * (i + 1));
                dr["Weight"] = 5.0;
                dr["Expires"] = DateTime.Now + TimeSpan.FromDays(7);
        <form runat="server" id="form1">
            <h3>BoundColumn DataFormatString Example</h3>
            <asp:DataGrid id="ItemsGrid" 
                BorderColor="black" BorderWidth="1" CellPadding="3"
                OnEditCommand="ItemsGrid_Edit" OnCancelCommand="ItemsGrid_Cancel" 
                OnUpdateCommand="ItemsGrid_Update" AutoGenerateColumns="false"
                runat="server" >

                <HeaderStyle backcolor="#aaaadd"></HeaderStyle>

                    <asp:EditCommandColumn EditText="Edit" CancelText="Cancel" 
                         UpdateText="Update" HeaderText="Edit Command Column">
                        <ItemStyle Wrap="False"></ItemStyle>
                        <HeaderStyle wrap="false"></HeaderStyle>

                    <asp:BoundColumn HeaderText="Item" DataField="Item" 
                                     ReadOnly="True" />

                    <asp:BoundColumn HeaderText="Quantity" DataField="Qty" 

                    <asp:BoundColumn HeaderText="Price" DataField="Price"
                                     DataFormatString="{0:c}" />

                    <asp:BoundColumn HeaderText="Weight" DataField="Weight" 
                                     ReadOnly="True" DataFormatString="{0:F3}" />

                    <asp:BoundColumn HeaderText="Expires" DataField="Expires" 
                                     ReadOnly="True" DataFormatString="{0:g}" />


.NET Framework
Available since 1.1
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