• Export GridView with Images to Word Excel and PDF Formats in ASP.Net


    In one of my previous articles I explained Export GridView with Images from database to Word, Excel and PDF Formats

    In this article I am explaining how to Export GridView to Microsoft Word, Microsoft Excel and Portable Document Format (PDF) which has images and pictures in it.  Here I am exporting a GridView which is displaying images stored on disk and the respective paths stored in SQL Server Database.

    Figure below describes how image paths are stored in the database table.

    The concept is quite simple whenever the Word or Excel file is transmitted to the client and the client opens it a call is made to the server and the images are downloaded from the server. Hence instead if the relative URL we will have to use the complete URL. So that the images are downloaded from the server

    Here I am using the same GridView which I used in my article Display Images in GridView Control using the path stored in SQL Server database to display images stored on disk in GridView. The only exporting I will be changing the URL of the image handler from relative to absolute URL. For example in the previous example the URL was

    Images/Garden.jpg

    Now it will be changed to

    http://localhost/Images/Garden.jpg

     

    Since Word, Excel or PDF files need complete URL of the image so that they can download the image from the server

    For doing this conversion I have the following function

    C#

    protected  string GetUrl(string imagepath)

    {

        string[] splits = Request.Url.AbsoluteUri.Split('/');

        if (splits.Length  >= 2)

        {

            string url = splits[0] + "//";

            for (int i = 2; i < splits.Length - 1; i++)

            {

                url += splits[i];

                url += "/";

            }

            return url +  imagepath;

        }

        return imagepath;

    }

    VB.Net

      Protected Function GetUrl(ByVal imagepath As String) As String

            Dim splits As String() = Request.Url.AbsoluteUri.Split("/"c)

            If splits.Length >= 2 Then

                Dim url As String = splits(0) & "//"

                For i As Integer = 2 To splits.Length - 2

                    url += splits(i)

                    url += "/"

                Next

                Return url + imagepath

            End If

            Return imagepath

        End Function

    And I am calling the function in the GridView in the following Manner. As you can see below I am passing the Image File Path to the GetUrl function which in returns the complete URL for the Image.

    <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns = "false"

    Font-Names = "Arial" >

    <Columns>

        <asp:BoundField DataField = "ID" HeaderText = "ID"

         ItemStyle-Height = "150" />

        <asp:BoundField DataField = "FileName" HeaderText = "Image Name"

         ItemStyle-Height = "150"/>

        <asp:TemplateField  ItemStyle-Height = "150" ItemStyle-Width = "170">

            <ItemTemplate>

                <asp:Image ID="Image1" runat="server"

                 ImageUrl = '<%# Eval("FilePath", GetUrl("{0}")) %>' />

            </ItemTemplate>

        </asp:TemplateField>

    </Columns>

    </asp:GridView>

    Figure Below displays the GridView with Images stored on disk and their relative paths stored in SQL Server Database

    When you do  View Source of the page in Browser you will notice that the relative URL have been converted to absolute one and the GetUrl function has done its job perfectly. Refer the figure below that displays the Source of the page with the complete URL of the image

    Now here is the code to Export the GridView in the Word, Excel and PDF Formats

       

         

    Word

     

    C#

    private void Word_Export()

    {

        Response.Clear();

        Response.Buffer = true;

        Response.AddHeader("content-disposition",

          "attachment;filename=GridViewExport.doc");

        Response.Charset = "";

        Response.ContentType = "application/vnd.ms-word ";

        StringWriter sw = new StringWriter();

        HtmlTextWriter hw = new HtmlTextWriter(sw);

        GridView1.AllowPaging = false;

        GridView1.DataBind();

        GridView1.RenderControl(hw);

        Response.Output.Write(sw.ToString());

        Response.Flush();

        Response.End();

    }

     

    VB.Net

    Private Sub Word_Export()

       Response.Clear()

       Response.Buffer = True

       Response.AddHeader("content-disposition", _

        "attachment;filename=GridViewExport.doc")

       Response.Charset = ""

       Response.ContentType = "application/vnd.ms-word "

       Dim sw As New StringWriter()

       Dim hw As New HtmlTextWriter(sw)

       GridView1.AllowPaging = False

       GridView1.DataBind()

       GridView1.RenderControl(hw)

       Response.Output.Write(sw.ToString())

       Response.Flush()

       Response.End()

    End Sub

    Figure below displays the Word document which contains exported GridView with images.

    Excel

                   

     

    C#

    private void Excel_Export()

    {

        Response.Clear();

        Response.Buffer = true;

        Response.AddHeader("content-disposition",

         "attachment;filename=GridViewExport.xls");

        Response.Charset = "";

        Response.ContentType = "application/vnd.ms-excel";

        StringWriter sw = new StringWriter();

        HtmlTextWriter hw = new HtmlTextWriter(sw);

        GridView1.AllowPaging = false;

        GridView1.DataBind();

        for (int i = 0; i < GridView1.Rows.Count; i++)

        {

            GridViewRow row = GridView1.Rows[i];

            //Apply text style to each Row

            row.Attributes.Add("class", "textmode");

        }

        GridView1.RenderControl(hw);

        //style to format numbers to string

        string style = @"<style> .textmode { mso-number-format:@; } </style>";

        Response.Write(style);

        Response.Output.Write(sw.ToString());

        Response.Flush();

        Response.End();

    }

       

                      

    VB.Net

    Private Sub Excel_Export()

       Response.Clear()

       Response.Buffer = True

       Response.AddHeader("content-disposition", _

        "attachment;filename=GridViewExport.xls")

       Response.Charset = ""

       Response.ContentType = "application/vnd.ms-excel"

       Dim sw As New StringWriter()

       Dim hw As New HtmlTextWriter(sw)

       GridView1.AllowPaging = False

       GridView1.DataBind()

       For i As Integer = 0 To GridView1.Rows.Count - 1

         Dim row As GridViewRow = GridView1.Rows(i)

        'Apply text style to each Row

         row.Attributes.Add("class", "textmode")

       Next

       GridView1.RenderControl(hw)

       'style to format numbers to string

       Dim style As String = "<style> .textmode " _

         & "{ mso-number-format:@; } </style>"

       Response.Write(style)

       Response.Output.Write(sw.ToString())

       Response.Flush()

       Response.End()

    End Sub

    Figure below displays the Excel Workbook which contains exported GridView with images.

    Portable Document Format (PDF)

     

    For exporting the GridView to PDF format I am using the iTextSharp Library that will be available with the source code of this example. Also you can download it from here.

           

     

    C#

    private void PDF_Export()

    {

        Response.ContentType = "application/pdf";

        Response.AddHeader("content-disposition",

            "attachment;filename=GridViewExport.pdf");

        Response.Cache.SetCacheability(HttpCacheability.NoCache);

        StringWriter sw = new StringWriter();

        HtmlTextWriter hw = new HtmlTextWriter(sw);

        GridView1.AllowPaging = false;

        GridView1.DataBind();

        GridView1.RenderControl(hw);

        StringReader sr = new StringReader(sw.ToString());

        Document pdfDoc = new Document(PageSize.A4, 10f, 10f, 10f, 0f);

        HTMLWorker htmlparser = new HTMLWorker(pdfDoc);

        PdfWriter.GetInstance(pdfDoc, Response.OutputStream);

        pdfDoc.Open();

        htmlparser.Parse(sr);

        pdfDoc.Close();

        Response.Write(pdfDoc);

        Response.End(); 

    }

     

    VB.Net

    Private Sub PDF_Export()

      Response.ContentType = "application/pdf"

      Response.AddHeader("content-disposition", _

       "attachment;filename=GridViewExport.pdf")

      Response.Cache.SetCacheability(HttpCacheability.NoCache)

      Dim sw As New StringWriter()

      Dim hw As New HtmlTextWriter(sw)

      GridView1.AllowPaging = False

      GridView1.DataBind()

      GridView1.RenderControl(hw)

      Dim sr As New StringReader(sw.ToString())

      Dim pdfDoc As New Document(PageSize.A4, 10.0F, 10.0F, 10.0F, 0.0F)

      Dim htmlparser As New HTMLWorker(pdfDoc)

      PdfWriter.GetInstance(pdfDoc, Response.OutputStream)

      pdfDoc.Open()

      htmlparser.Parse(sr)

      pdfDoc.Close()

      Response.Write(pdfDoc)

      Response.End()

    End Sub

    Figure below displays the PDF Document which contains exported GridView with images.


      

    Finally the method that one should not forget is the below otherwise the GridView export will throw the Error

    Control 'GridView1' of type 'GridView' must be placed inside a form tag with runat=server.

    C#.Net

    public override void VerifyRenderingInServerForm(Control control)

    {

        /* Verifies that the control is rendered */

    }

    VB.Net

    Public Overloads Overrides Sub VerifyRenderingInServerForm(

    ByVal control As Control)

            ' Verifies that the control is rendered

    End Sub

    This completes the article. You can download the source in C# and Vb.Net using the link below.

    Download

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  • 原文地址:https://www.cnblogs.com/happy-Chen/p/3638539.html
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