Esporta in file Excel in MVC3 ASP.net

Question

Ho il seguente codice in un controller e vorrei salvarlo tutto in un file excel, ma non riesco a far visualizzare al browser la finestra di dialogo di salvataggio del file.

public ContentResult Export(...) { 
StringBuilder sb = new StringBuilder(); 
      sb.Append("<table border='" + "2px" + "'b>"); 
      //write column headings 
      sb.Append("<tr>"); 
      foreach (System.Data.DataColumn dc in dt.Columns) { 
       sb.Append("<td><b><font face=Arial size=2>" + dc.ColumnName + "</font></b></td>"); 
      } 
      sb.Append("</tr>"); 

      //write table data 
      foreach (System.Data.DataRow dr in dt.Rows) { 
       sb.Append("<tr>"); 
       foreach (System.Data.DataColumn dc in dt.Columns) { 
        sb.Append("<td><font face=Arial size=" + "14px" + ">" + dr[dc].ToString() + "</font></td>"); 
       } 
       sb.Append("</tr>"); 
      } 
      sb.Append("</table>"); 

      this.Response.AddHeader("Content-Disposition", "Employees.xls"); 
      this.Response.ContentType = "application/vnd.ms-excel"; 
      return this.Content(sb.ToString()); 
} 

Grazie mille in anticipo!

Answer 1

Prova questa:

public ActionResult Export(...) { 
     StringBuilder sb = new StringBuilder(); 
     sb.Append("<table border='" + "2px" + "'b>"); 
     //write column headings 
     sb.Append("<tr>"); 
     foreach (System.Data.DataColumn dc in dt.Columns) { 
      sb.Append("<td><b><font face=Arial size=2>" + dc.ColumnName + "</font></b></td>"); 
     } 
     sb.Append("</tr>"); 

     //write table data 
     foreach (System.Data.DataRow dr in dt.Rows) { 
      sb.Append("<tr>"); 
      foreach (System.Data.DataColumn dc in dt.Columns) { 
       sb.Append("<td><font face=Arial size=" + "14px" + ">" + dr[dc].ToString() + "</font></td>"); 
      } 
      sb.Append("</tr>"); 
     } 
     sb.Append("</table>"); 

     this.Response.AddHeader("Content-Disposition", "Employees.xls"); 
     this.Response.ContentType = "application/vnd.ms-excel"; 
     byte[] buffer = System.Text.Encoding.UTF8.GetBytes(sb.ToString()); 
      return File(buffer, "application/vnd.ms-excel"); 
} 

Answer 2

Non sono sicuro che abbia qualcosa da fare che stai usando ContentResult. Ma di recente ho utilizzato una propria classe che eredita da FileResult, che aiuta a generare Excel-esportazioni (mi dispiace, i commenti sono in tedesco):

/// <summary> 
/// Generiert eine Excel-Datei 
/// </summary> 
public sealed class ExcelFileResult : FileResult 
{ 
    private DataTable dt; 
    private TableStyle tableStyle; 
    private TableItemStyle headerStyle; 
    private TableItemStyle itemStyle; 

    /// <summary> 
    /// Z.Bsp. "Exportdatum: {0}" (Standard-Initialisierung) - wenn leerer String, wird Exportdatum 
    /// nicht angegeben. 
    /// </summary> 
    public string TitleExportDate { get; set; } 
    /// <summary> 
    /// Titel des Exports, wird im Sheet oben links ausgegeben 
    /// </summary> 
    public string Title { get; set; } 


    /// <summary> 
    /// Konstruktor 
    /// </summary> 
    /// <param name="dt">Die zu exportierende DataTable</param> 
    public ExcelFileResult(DataTable dt) 
     : this(dt, null, null, null) 
    { } 

    /// <summary> 
    /// Konstruktor 
    /// </summary> 
    /// <param name="dt">Die zu exportierende DataTable</param> 
    /// <param name="tableStyle">Styling für gesamgte Tabelle</param> 
    /// <param name="headerStyle">Styling für Kopfzeile</param> 
    /// <param name="itemStyle">Styling für die einzelnen Zellen</param> 
    public ExcelFileResult(DataTable dt, TableStyle tableStyle, TableItemStyle headerStyle, TableItemStyle itemStyle) 
     : base("application/ms-excel") 
    { 
     this.dt = dt; 
     TitleExportDate = "Exportdatum: {0}"; 
     this.tableStyle = tableStyle; 
     this.headerStyle = headerStyle; 
     this.itemStyle = itemStyle; 

     // provide defaults 
     if (this.tableStyle == null) 
     { 
      this.tableStyle = new TableStyle(); 
      this.tableStyle.BorderStyle = BorderStyle.Solid; 
      this.tableStyle.BorderColor = Color.Black; 
      this.tableStyle.BorderWidth = Unit.Parse("2px"); 
     } 
     if (this.headerStyle == null) 
     { 
      this.headerStyle = new TableItemStyle(); 
      this.headerStyle.BackColor = Color.LightGray; 
     } 
    } 


    protected override void WriteFile(HttpResponseBase response) 
    { 
     // Create HtmlTextWriter 
     StringWriter sw = new StringWriter(); 
     HtmlTextWriter tw = new HtmlTextWriter(sw); 

     // Build HTML Table from Items 
     if (tableStyle != null) 
      tableStyle.AddAttributesToRender(tw); 
     tw.RenderBeginTag(HtmlTextWriterTag.Table); 

     // Create Title Row 
     tw.RenderBeginTag(HtmlTextWriterTag.Tr); 
     tw.AddAttribute(HtmlTextWriterAttribute.Colspan, (dt.Columns.Count - 2).ToString()); 
     tw.RenderBeginTag(HtmlTextWriterTag.Td); 
     tw.Write(Title); 
     tw.RenderEndTag(); 
     tw.AddAttribute(HtmlTextWriterAttribute.Colspan, "2"); 
     tw.RenderBeginTag(HtmlTextWriterTag.Td); 
     if (TitleExportDate != string.Empty) 
      tw.WriteLineNoTabs(string.Format(TitleExportDate, DateTime.Now.ToString("dd.MM.yyyy"))); 
     tw.RenderEndTag(); 

     // Create Header Row 
     tw.RenderBeginTag(HtmlTextWriterTag.Tr); 
     DataColumn col = null; 
     for (Int32 i = 0; i <= dt.Columns.Count - 1; i++) 
     { 
      col = dt.Columns[i]; 
      if (headerStyle != null) 
       headerStyle.AddAttributesToRender(tw); 
      tw.RenderBeginTag(HtmlTextWriterTag.Th); 
      tw.RenderBeginTag(HtmlTextWriterTag.Strong); 
      tw.WriteLineNoTabs(col.ColumnName); 
      tw.RenderEndTag(); 
      tw.RenderEndTag(); 
     } 
     tw.RenderEndTag(); 

     // Create Data Rows 
     foreach (DataRow row in dt.Rows) 
     { 
      tw.RenderBeginTag(HtmlTextWriterTag.Tr); 
      for (Int32 i = 0; i <= dt.Columns.Count - 1; i++) 
      { 
       if (itemStyle != null) 
        itemStyle.AddAttributesToRender(tw); 
       tw.RenderBeginTag(HtmlTextWriterTag.Td); 
       tw.WriteLineNoTabs(HttpUtility.HtmlEncode(row[i])); 
       tw.RenderEndTag(); 
      } 
      tw.RenderEndTag(); // /tr 
     } 

     tw.RenderEndTag(); // /table 

     // Write result to output-stream 
     Stream outputStream = response.OutputStream; 
     byte[] byteArray = Encoding.Default.GetBytes(sw.ToString()); 
     response.OutputStream.Write(byteArray, 0, byteArray.GetLength(0)); 
    } 
} 

Poi nel controller:

/// <summary> 
    /// Excel-Export 
    /// </summary> 
    public ExcelFileResult ExportExcel() 
    { 
     // DataTable dt = -- > get your data 
     ExcelFileResult actionResult = new ExcelFileResult(dt) { FileDownloadName = "yourFileName.xls" }; 
     return actionResult; 
    }