In this article we are discuss in DevExpress How to set the column width when exporting GridView to Excel

Change to Export Width to Using GridViewColumn.ExportWidth property

public static GridViewSettingsReportBookingSummaryExportGridViewSettings()
{
   var settings = new GridViewSettings
   {
CallbackRouteValues = new { Controller = "ReportGenerator", Action = "gvSummaryDtl" },
Name = "gvSummary"
   };
   settings.SettingsExport.ExportedRowType = GridViewExportedRowType.All;
   settings.KeyFieldName = "{ numID }";
   settings.Settings.ShowGroupPanel = true;
   settings.Settings.ShowFilterRowMenu = true;
   settings.Settings.ShowFooter = true;
   settings.Settings.ShowGroupFooter = GridViewGroupFooterMode.VisibleAlways;


   settings.Columns.Add(col => {
      col.FieldName = "Name";
      col.ExportWidth = 500;

   });
}