如何在Excel中创建自动补全功能？

Question

In my application, there is a need to create an excel file which should have an auto-completion feature. Suppose I am fetching some values "Data 1","Data 2" from the database, after fetching I want to bind those values to a particular column of excel. So when a user types something it would prompt "Data 1","Data 2"...

How to achieve this? help needed

Answer 1

You are describing a feature called Data Validation. It's main purpose is to limit the possible values of a cell to a certain range but, as you have spotted, this has the handy side-effect of having Excel show a drop down of the available values.

You can do something like this using various openXML libraries which allow you to create .xlsx files in .NET code. I like EPPlus which would let you do something like this:

static void Main(string[] args)
{
    var fInfo = new FileInfo("output.xlsx");
    using (var excel = new ExcelPackage())
    {
        var sht1 = excel.Workbook.Worksheets.Add("DataSheet1");
        sht1.Cells[1,1].Value = "Occupation:";
        var validation = sht1.DataValidations.AddListValidation("A2");
        foreach(var allowedValue in GetAllowedValues())
        {
            validation.Formula.Values.Add(allowedValue);
        }
        excel.SaveAs(fInfo);
    }
}

private static IEnumerable<string> GetAllowedValues()
{
    return new string []{"Doctor","Baker","Candlestick Maker"};
} 

This gives the dropdown list you are referring to (my screengrab is from LibreOffice but you will see the same effect in Excel):