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Simple Code to export plain text only from Gridview to CSV (no formatting)

Posted on 2013-01-04
13
1,988 Views
Last Modified: 2013-01-26
I have the following code in Test.vb:

    Protected Sub ibExportPlain_Click(ByVal sender As Object, ByVal args As EventArgs) Handles ibExportPlain.Click, lbExportPlain.Click
        GridViewExportUtil.Export("Export.csv", Me.gvCA)

    End Sub

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This code accesses GridViewExportUtil.cs which has the following code:

using System;
using System.Data;
using System.Configuration;
using System.IO;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

/// <summary>
/// 
/// </summary>
public class GridViewExportUtil
{
    /// <summary>
    /// 
    /// </summary>
    /// <param name="fileName"></param>
    /// <param name="gv"></param>
    public static void Export(string fileName, GridView gv)
    {
        HttpContext.Current.Response.Clear();
        HttpContext.Current.Response.AddHeader(
            "content-disposition", string.Format("attachment; filename={0}", fileName));
        HttpContext.Current.Response.ContentType = "text/plain";

        using (StringWriter sw = new StringWriter())
        {
            using (HtmlTextWriter htw = new HtmlTextWriter(sw))
            {
                //  Create a form to contain the grid
                Table table = new Table();

                //  add the header row to the table
                if (gv.HeaderRow != null)
                {
                    GridViewExportUtil.PrepareControlForExport(gv.HeaderRow);
                    table.Rows.Add(gv.HeaderRow);
                    for (int j = 0; j < gv.Columns.Count; j++)
                    {
                        gv.HeaderRow.Cells[j].Style.Add("background-color", "cornflowerblue");
                    }
                }

                //  add each of the data rows to the table
                foreach (GridViewRow row in gv.Rows)
                {
                    GridViewExportUtil.PrepareControlForExport(row);
                    table.Rows.Add(row);
                    
                }
                //  add the footer row to the table
                if (gv.FooterRow != null)
                {
                    GridViewExportUtil.PrepareControlForExport(gv.FooterRow);
                    table.Rows.Add(gv.FooterRow);
                }

                //  render the table into the htmlwriter
                table.RenderControl(htw);

                //  render the htmlwriter into the response
                HttpContext.Current.Response.Write(sw.ToString());
                HttpContext.Current.Response.End();
            }
        }
    }

    /// <summary>
    /// Replace any of the contained controls with literals
    /// </summary>
    /// <param name="control"></param>
    private static void PrepareControlForExport(Control control)
    {
        for (int i = 0; i < control.Controls.Count; i++)
        {
            Control current = control.Controls[i];
            if (current is LinkButton)
            {
                control.Controls.Remove(current);
                control.Controls.AddAt(i, new LiteralControl((current as LinkButton).Text));
            }
            else if (current is ImageButton)
            {
                control.Controls.Remove(current);
                control.Controls.AddAt(i, new LiteralControl((current as ImageButton).AlternateText));
            }
            else if (current is Image)
            {
                control.Controls.Remove(current);
                control.Controls.AddAt(i, new LiteralControl((current as Image).AlternateText));
            }
            else if (current is Label)
            {
                control.Controls.Remove(current);
                control.Controls.AddAt(i, new LiteralControl((current as Label).Text));
            }
            else if (current is HyperLink)
            {
                control.Controls.Remove(current);
                control.Controls.AddAt(i, new LiteralControl((current as HyperLink).Text));
            }
            else if (current is DropDownList)
            {
                control.Controls.Remove(current);
                control.Controls.AddAt(i, new LiteralControl((current as DropDownList).SelectedItem.Text));
            }
            else if (current is CheckBox)
            {
                control.Controls.Remove(current);
                control.Controls.AddAt(i, new LiteralControl((current as CheckBox).Checked ? "True" : "False"));
            }

            if (current.HasControls())
            {
                GridViewExportUtil.PrepareControlForExport(current);
            }
        }
    }
}

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I need help with the following:
(1)  The export works great except the output still includes the background color of the last column - I can't remove it for some reason.

(2) Since the GridViewExportUtil.cs removes the images from the first column and replaces it with the Alt text, the first column is blank.  Is there a way to remove this column?

I just want a plain csv file which opens in excel...
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Comment
Question by:badzster
  • 5
  • 3
  • 2
  • +3
13 Comments
 

Author Comment

by:badzster
ID: 38746127
Here is the Gridview code in Test.aspx:

<asp:GridView ID="gvCA" runat="server" AutoGenerateColumns="False" 
            CellPadding="4" DataKeyNames="ID" DataSourceID="SQLTable" 
            ForeColor="#333333" GridLines="None" CssClass="GridView" AllowSorting="True" Width="100%" >
            <AlternatingRowStyle BackColor="White" />
            <Columns>
                <asp:TemplateField>
                    <EditItemTemplate>
                        <asp:TextBox ID="TextBox6" runat="server" Text='<%# Eval("STATUSURL") %>'></asp:TextBox>
                    </EditItemTemplate>
                    <ItemTemplate>
                        <asp:Image ID="Image1" runat="server" ImageUrl='<%# Eval("STATUSURL") %>' />
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="ID" SortExpression="ID">
                    <ItemTemplate>
                        <asp:Label ID="Label1" runat="server" Text='<%# Bind("ID") %>'></asp:Label>
                    </ItemTemplate>
                    <EditItemTemplate>
                        <asp:Label ID="Label1" runat="server" Text='<%# Eval("ID") %>'></asp:Label>
                    </EditItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="DESCRIPTION" >
                    <ItemTemplate>
                        <asp:LinkButton ID="LinkButton2" runat="server" onclick="LinkButton2_Click" 
                            Text='<%#Eval("DESCRIPTION")%>'></asp:LinkButton>
                    </ItemTemplate>
                </asp:TemplateField>  
                <asp:TemplateField HeaderText="SOURCE" SortExpression="SOURCE">
                    <ItemTemplate>
                        <asp:Label ID="Label2" runat="server" Text='<%# Bind("SOURCE") %>'></asp:Label>
                    </ItemTemplate>
                    <EditItemTemplate>
                        <asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("SOURCE") %>'></asp:TextBox>
                    </EditItemTemplate>
                    <ItemStyle Width="200px" />
                </asp:TemplateField>
                <asp:TemplateField HeaderText="ASSIGNED_TO" SortExpression="ASSIGNED_TO">
                    <ItemTemplate>
                        <asp:Label ID="Label3" runat="server" Text='<%# Bind("ASSIGNED_TO") %>'></asp:Label>
                    </ItemTemplate>
                    <EditItemTemplate>
                        <asp:TextBox ID="TextBox2" runat="server" Text='<%# Bind("ASSIGNED_TO") %>'></asp:TextBox>
                    </EditItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="DUE_DATE" SortExpression="DUE_DATE">
                    <ItemTemplate>
                        <asp:Label ID="lblDueDate" runat="server" Text='<%# Bind("DUE_DATE", "{0:d}") %>'></asp:Label>
                    </ItemTemplate>
                    <EditItemTemplate>
                        <asp:TextBox ID="TextBox3" runat="server" Text='<%# Bind("DUE_DATE") %>'></asp:TextBox>
                    </EditItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="STATUS" SortExpression="STATUS">
                    <ItemTemplate>
                        <asp:Label ID="Label5" runat="server" Text='<%# Bind("STATUS") %>'></asp:Label>
                    </ItemTemplate>
                    <EditItemTemplate>
                        <asp:TextBox ID="TextBox4" runat="server" Text='<%# Bind("STATUS") %>'></asp:TextBox>
                    </EditItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="FUTURE_POTENTIAL_RISK" 
                    SortExpression="FUTURE_POTENTIAL_RISK">
                    <ItemTemplate>
                        <asp:Label ID="Label6" runat="server" 
                            Text='<%# Bind("FUTURE_POTENTIAL_RISK") %>'></asp:Label>
                    </ItemTemplate>
                    <EditItemTemplate>
                        <asp:TextBox ID="TextBox5" runat="server" 
                            Text='<%# Bind("FUTURE_POTENTIAL_RISK") %>'></asp:TextBox>
                    </EditItemTemplate>
                </asp:TemplateField>
            </Columns>
            <EditRowStyle BackColor="#2461BF" />
            <EmptyDataTemplate>
                Empty
            </EmptyDataTemplate>
            <FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
            <HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" 
                CssClass="Gridview HeaderStyle" Width="100%" HorizontalAlign="Left" />
            <PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" />
            <RowStyle BackColor="#EFF3FB" />
            <SelectedRowStyle BackColor="#D1DDF1" Font-Bold="True" ForeColor="#333333" />
            <SortedAscendingCellStyle BackColor="#F5F7FB" />
            <SortedAscendingHeaderStyle BackColor="#6D95E1" />
            <SortedDescendingCellStyle BackColor="#E9EBEF" />
            <SortedDescendingHeaderStyle BackColor="#4870BE" />

        </asp:GridView>

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0
 
LVL 18

Expert Comment

by:dj_alik
ID: 38747111
Why did not work with underlying data source of the grid view?
0
 

Author Comment

by:badzster
ID: 38747505
Would you have a sample?  I presume you mean why didn't I export directly from the datasource rather than the gridview??
0
 
LVL 35

Expert Comment

by:Miguel Oz
ID: 38747586
If you just need plain text you need to remove the style code below used in the header in Export method:
for (int j = 0; j < gv.Columns.Count; j++)
                    {
                        gv.HeaderRow.Cells[j].Style.Add("background-color", "cornflowerblue");
                    }

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Regarding second issue: Remove the first column of the datatable using
RemoveAt method
table.Columns.RemoveAt(0);

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before render the table into the htmlwriter.
0
 
LVL 10

Expert Comment

by:P1ST0LPETE
ID: 38747792
Would you have a sample?  I presume you mean why didn't I export directly from the datasource rather than the gridview??
I agree that you should do the export from the underlying data source.  Attempting to export from the GridView itself just seems dirty.

Here is an example of exporting to CSV format from a SqlDataReader:

public String ExportToCsv(SqlDataReader reader)
{
    var csv = new StringBuilder();
            
    if (reader != null && reader.HasRows)
    {
        var count = reader.FieldCount;

        for (int i = 0; i < count; i++)
        {
            csv.AppendFormat("{0}{1}", reader.GetName(i), i < count - 1 ? "," : "\r\n");
        }

        while (reader.Read())
        {
            for (int i = 0; i < count; i++)
            {
                csv.AppendFormat("{0}{1}", Convert.ToString(reader[i]), i < count - 1 ? "," : "\r\n");
            }
        }
    }

    return csv.ToString();
}

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0
 
LVL 23

Expert Comment

by:Roopesh Reddy
ID: 38748099
Hi,

Check this article - http://www.aspsnippets.com/Articles/Export-GridView-To-Word-Excel-PDF-CSV-Formats-in-ASP.Net.aspx

Well explained all the possible formats in which you can export the data!

Hope it helps u...
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Author Comment

by:badzster
ID: 38748197
Tried the following code from the suggested link (http://www.aspsnippets.com/Articles/Export-GridView-To-Word-Excel-PDF-CSV-Formats-in-ASP.Net.aspx) but only the headers appear - no rows...definitely rows in gridview though??


protected void btnExportCSV_Click(object sender, EventArgs e)
{
    Response.Clear();
    Response.Buffer = true;
    Response.AddHeader("content-disposition",
     "attachment;filename=GridViewExport.csv");
    Response.Charset = "";
    Response.ContentType = "application/text";
 
    GridView1.AllowPaging = false;
    GridView1.DataBind();
 
    StringBuilder sb = new StringBuilder();
    for (int k = 0; k < GridView1.Columns.Count; k++)
    {
        //add separator
        sb.Append(GridView1.Columns[k].HeaderText + ',');
    }
    //append new line
    sb.Append("\r\n");
    for (int i = 0; i < GridView1.Rows.Count; i++)
    {
        for (int k = 0; k < GridView1.Columns.Count; k++)
        {
            //add separator
            sb.Append(GridView1.Rows[i].Cells[k].Text + ',');
        }
        //append new line
        sb.Append("\r\n");
    }
    Response.Output.Write(sb.ToString());
    Response.Flush();
    Response.End();
}

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0
 
LVL 23

Expert Comment

by:Roopesh Reddy
ID: 38748815
Hi,

I created a sample code for you -

<asp:GridView runat="server" ID="gridView"  AutoGenerateColumns="false">
        <Columns>
            <asp:TemplateField HeaderText="A" ShowHeader="true" >
                <ItemTemplate>
                    <asp:Literal Text='<%#Eval("Name")%>' ID="txt1" runat="server" />
                </ItemTemplate>
            </asp:TemplateField>
            <asp:TemplateField HeaderText="B">
                <ItemTemplate>
                    <asp:Literal runat="server" ID="txt2" Text='<%#Eval("Company")%>'  />
                </ItemTemplate>
            </asp:TemplateField>
            <asp:TemplateField HeaderText="C">
                <ItemTemplate>
                    <asp:Literal runat="server" ID="txt3" Text='<%#Eval("Category")%>' />
                </ItemTemplate>
            </asp:TemplateField>
        </Columns>
    </asp:GridView>

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protected void Page_Load(object sender, EventArgs e)
        {
            var rows = new []
            {
                new
                {
                    Name="Bill Gates", Company="Microsoft",Category = "Software"
                },
                new
                {
                    Name="Steve Jobs",Company="Apple",Category = "Software"
                },
                new
                {
                    Name="Larry Page",Company="Google",Category = "Software"
                }

            };

            gridView.DataSource = rows;
            gridView.DataBind();

            Response.Clear();
            Response.Buffer = true;
            Response.AddHeader("content-disposition",
             "attachment;filename=GridViewExport.csv");
            Response.Charset = "";
            Response.ContentType = "application/text";

            

            StringBuilder sb = new StringBuilder();
            for (int k = 0; k < gridView.Columns.Count; k++)
            {
                //add separator
                sb.Append(gridView.Columns[k].HeaderText + ',');
            }
            //append new line
            sb.Append("\r\n");
            for (int i = 0; i < gridView.Rows.Count; i++)
            {
                    Literal lt =  gridView.Rows[i].FindControl("txt1") as Literal;
                    //add separator
                    sb.Append(lt.Text + ',');

                    lt = gridView.Rows[i].FindControl("txt2") as Literal;
                    //add separator
                    sb.Append(lt.Text + ',');

                    lt = gridView.Rows[i].FindControl("txt3") as Literal;
                    //add separator
                    sb.Append(lt.Text + ',');

                    //append new line
                    sb.Append("\r\n");

            }
                           
            Response.Output.Write(sb.ToString());
            Response.Flush();
            Response.End();

        }

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The above is a sample code, which it shows how to export the data as CSV format!

Moreover, you would have been using Templates instead of Auto Generated columns and hence it is not exporting the data!

http://forums.asp.net/t/1736121.aspx/1

Hope it helps u...
0
 

Author Comment

by:badzster
ID: 38749177
Thanks for the effort - I've tried the code below (converted to vb) but keep getting the error:

Object reference not set to an instance of an object.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:


Line 293:            Dim lt As Literal = TryCast(gvCA.Rows(i).FindControl("Label1"), Literal)
Line 294:            'add separator
Line 295:            sb.Append(lt.Text + ","c)



Any reason you can think of?


        gvCA.DataBind()

        Response.Clear()
        Response.Buffer = True
        Response.AddHeader("content-disposition", "attachment;filename=GridViewExport.csv")
        Response.Charset = ""
        Response.ContentType = "application/text"



        Dim sb As New StringBuilder()
        For k As Integer = 0 To gvCA.Columns.Count - 1
            'add separator
            sb.Append(gvCA.Columns(k).HeaderText + ","c)
        Next
        'append new line
        sb.Append(vbCr & vbLf)
        For i As Integer = 0 To gvCA.Rows.Count - 1
            Dim lt As Literal = TryCast(gvCA.Rows(i).FindControl("Label1"), Literal)
            'add separator
            sb.Append(lt.Text + ","c)

            lt = TryCast(gvCA.Rows(i).FindControl("LinkButton2"), Literal)
            'add separator
            sb.Append(lt.Text + ","c)

            lt = TryCast(gvCA.Rows(i).FindControl("Label2"), Literal)
            'add separator
            sb.Append(lt.Text + ","c)

            lt = TryCast(gvCA.Rows(i).FindControl("Label3"), Literal)
            'add separator
            sb.Append(lt.Text + ","c)

            lt = TryCast(gvCA.Rows(i).FindControl("lblDueDate"), Literal)
            'add separator
            sb.Append(lt.Text + ","c)

            lt = TryCast(gvCA.Rows(i).FindControl("Label5"), Literal)
            'add separator
            sb.Append(lt.Text + ","c)

            lt = TryCast(gvCA.Rows(i).FindControl("Label6"), Literal)
            'add separator
            sb.Append(lt.Text + ","c)
            'append new line

            sb.Append(vbCr & vbLf)
        Next

        Response.Output.Write(sb.ToString())
        Response.Flush()
        Response.[End]()

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0
 
LVL 19

Expert Comment

by:Manoj Patil
ID: 38749178
0
 

Author Comment

by:badzster
ID: 38749190
Already tried that as per my post on 2013-01-06 at 09:19:14  ID: 38748197

I just wish there was a way to export directly from the SQLDataSource - however the sample given by: P1ST0LPETEPosted on 2013-01-06 at 01:30:03ID: 38747792 doesn't seem to specify/allow you to input the specific SQLDataSource...maybe I'm missing something.
0
 
LVL 23

Expert Comment

by:Roopesh Reddy
ID: 38749791
Hi,

Yeah! It's because you have used  asp:Label control and while casting you have used asp:Literal control, which leads to the NullReference Exception!

Consider the following statement in your code -

Dim lt As Literal = TryCast(gvCA.Rows(i).FindControl("Label1"), Literal)

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You have asp:Label in the GridView, but you are casting it to asp:Literal which is not correct.

In my example, i have used Literals, so i have used same in the code behind as well -

<asp:Literal Text='<%#Eval("Name")%>' ID="txt1" runat="server" />

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So, you have to use the same control which you have used in the asp:GridView and cast it accordingly!

If you still has issues, do show us the asp:GridView code, so that we will give the equivalent code!

Hope it helps u...
0
 
LVL 10

Accepted Solution

by:
P1ST0LPETE earned 500 total points
ID: 38757067
I just wish there was a way to export directly from the SQLDataSource - however the sample given by: P1ST0LPETEPosted on 2013-01-06 at 01:30:03ID: 38747792 doesn't seem to specify/allow you to input the specific SQLDataSource...maybe I'm missing something.

Sorry, for not explaining more in my first post.  As far as the export is concerned, you can do away with the SqlDataSource completely. (I would say don't use a SqlDataSource control period - but that's another topic).  Anyway, code should look similar to this:

Html Markup:
<asp:Button runat="server" Text="Button" ID="ExportButton" OnClick="ExportButton_Click" />

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Code Behind:
public void ExportButton_Click(object sender, EventArgs e)
{
    var connection = new SqlConnection("Server=myServerAddress;Database=myDataBase;User Id=myUsername;Password=myPassword;");
    var command = new SqlCommand("SELECT * FROM [TableName]", connection);
    var reader = GetDataReader(command);
    var csv = ExportToCsv(reader);

    Response.Clear();
    Response.AppendHeader("content-disposition", "attachment; filename=" + DateTime.Now + ".csv");
    Response.ContentType = "text/csv";
    Response.Write(csv);
    Response.Flush();
    Response.End();
}

private SqlDataReader GetDataReader(SqlCommand command)
{
    SqlDataReader reader = null;

    try
    {
        command.CommandType = CommandType.Text;
        command.Connection.Open();
        reader = command.ExecuteReader();
    }
    catch (Exception exception)
    {
        //log exception and/or rethrow

        if (reader != null)
        {
            reader.Dispose();
            reader = null;
        }

        command.Connection.Close();
        command.Dispose();
    }

    return reader;
}

private String ExportToCsv(SqlDataReader reader)
{
    var csv = new StringBuilder();

    if (reader != null && reader.HasRows)
    {
        var count = reader.FieldCount;

        for (int i = 0; i < count; i++)
        {
            csv.AppendFormat("{0}{1}", reader.GetName(i), i < count - 1 ? "," : "\r\n");
        }

        while (reader.Read())
        {
            for (int i = 0; i < count; i++)
            {
                csv.AppendFormat("{0}{1}", Convert.ToString(reader[i]), i < count - 1 ? "," : "\r\n");
            }
        }
    }

    return csv.ToString();
}

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