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Export to Excel - C#

Posted on 2010-08-19
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Last Modified: 2012-05-10
Hello all,
I need to create a button to export data from sql to excel.
It needs to call a procedure that selects data from a database my 2 questions are:
1- how to export to excel?
2- how to have the title of each column on excel

thanks,
Caliu
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Question by:Romacali
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Expert Comment

by:Anil Golamari
ID: 33478565
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Accepted Solution

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yesthatbob earned 500 total points
ID: 33478839
Well, in my opinion, your best bet is to write your data to a CSV (comma separated value) file. Excel can open CSV files natively (you won't need to do an import). Your first row in the CSV file can contain your column names. See the code below for an example...
// This code assumes you have a DataSet named ds that contains your data

			// Open a file for writing the values
			StringBuilder rowData = new StringBuilder();
			TextWriter tw = new StreamWriter(@"C:\Test.csv", false, Encoding.UTF8);
			
			// Get all of the column names...
			foreach (DataColumn col in ds.Tables[0].Columns)
			{
				// ...and write them to the first row
				rowData.AppendFormat("{0},", col.ColumnName);
			}

			// Remove last comma
			if (rowData.ToString().EndsWith(","))
				rowData.Remove(rowData.Length - 1, 1);
			
			// Write header to file
			tw.WriteLine(rowData);
			rowData.Clear();

			// Get each data row...
			foreach (DataRow row in ds.Tables[0].Rows)
			{
				// ...and each field in the row...
				foreach (object field in row.ItemArray)
				{
					// ...and write them to a new row
					rowData.AppendFormat("{0},", field.ToString());
				}

				// Remove last comma
				if (rowData.ToString().EndsWith(","))
					rowData.Remove(rowData.Length - 1, 1);

				// Write data to file
				tw.WriteLine(rowData);
				rowData.Clear();
			}

			// Clean up
			tw.Flush();
			tw.Close();

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Expert Comment

by:Daniel Junges
ID: 33482706
Here an working funktion
public static void exportToExcel( System.Windows.Forms.DataGridView dg, string filePath, string sheetName )
{
    string stmt = "";
    System.Data.OleDb.OleDbConnection connection = null;
    try { System.IO.File.Delete( filePath ); } catch ( Exception ) { }
    try {
        connection = ToolsDB.CreateOleDbConnectionToExcell( filePath );
        connection.Open();

        // Create the colum names
        string tableName = sheetName;
        stmt = "CREATE TABLE " + tableName + " (";
        foreach ( System.Windows.Forms.DataGridViewColumn column in dg.Columns ) {
            if ( column.Visible ) {
                stmt += column.HeaderText;

                switch ( column.ValueType.ToString() ) {
                    case "System.Int32":
                    case "System.Int16":
                    case "System.Int64":
                        stmt += " int,";
                        break;
                    case "System.Double":
                    case "System.Decimal":
                    case "System.Float":
                        stmt += " float,";
                        break;
                    case "System.DateTime":
                        stmt += " date,";
                        break;
                    default:
                        stmt += " char(255),";
                        break;
                }
            }
        }
        stmt = stmt.Substring( 0, stmt.Length - 1 );
        stmt += ")";
        System.Data.OleDb.OleDbCommand cmd = new System.Data.OleDb.OleDbCommand( stmt, connection );
        cmd.ExecuteNonQuery();

        // copy data
        foreach ( System.Windows.Forms.DataGridViewRow row in dg.Rows ) {
            string stmt1 = "INSERT INTO [" + tableName + "] (";
            string stmt2 = " VALUES (";
            foreach ( System.Windows.Forms.DataGridViewColumn column in dg.Columns ) {
                if ( column.Visible ) {

                    stmt1 += column.HeaderText + ",";

                    switch ( column.ValueType.ToString() ) {
                        case "System.Int32":
                        case "System.Int16":
                        case "System.Int64":
                            stmt2 += row.Cells[column.Name].Value.ToString() + ",";
                            break;
                        case "System.Double":
                        case "System.Decimal":
                        case "System.Float":
                            stmt2 += String.Format( "{0,2:f2}", row.Cells[column.Name].Value ).Replace( ",", "." ) + ",";
                            break;
                        case "System.DateTime":
                            stmt2 += "'" + ((DateTime)row.Cells[column.Name].Value).ToString( "dd/MM/yyyy" ) + "',";
                            break;
                        default:
                            string text = row.Cells[column.Name].Value.ToString();
                            if ( text.Length > 254 ) text = text.Substring( 0, 254 );
                            stmt2 += "'" + text + "',";
                            break;
                    }
                }
            }
            stmt1 = stmt1.Substring( 0, stmt1.Length - 1 );
            stmt2 = stmt2.Substring( 0, stmt2.Length - 1 );
            stmt1 += ")";
            stmt2 += ")";
            stmt = stmt1 + stmt2;
            cmd = new System.Data.OleDb.OleDbCommand( stmt, connection );
            cmd.ExecuteNonQuery();
        }

    } catch ( Exception ex ) {
    }
    connection.Close();
}

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Expert Comment

by:Daniel Junges
ID: 33482710
you can adapt this function do DataSet if you want, to export the data it uses oledb
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