在DataGridView中使用自定义格式化程序 [英] Using a custom formatter in a DataGridView

问题描述

那么，也许这是一个糟糕的设计;我不知道。但是说我有一个 DataTable ，列有一个包含 int 值的列;这些值实际上意味着代表我在项目中的一些枚举类型。

喜欢做的是将一个 DataGridView 绑定到此表，并且列显示的名称为枚举，而不是整数值0或1或任何其他。

我认为的一个选项是做整个规范化的事情：在 DataSet 与枚举中的名称，键入枚举值，并让我

但是这是一个枚举 - 具体想法我想知道，一般来说，我可以为给定的类型编写自己的 IFormatProvider 和 ICustomFormatter implementation *并且使用该格式化器来控制如何在 DataGridView 控件（或者真正在任何控件）的给定列中显示值。

_{*这只是我怀疑它会做的，如果我问的是可能的话。我根本就不会使用这些接口。}

解决方案

ICustomFormatter ，但由于 DataGridView 的某些延迟，您需要实际告诉您如何应用格式化程序。

首先将 column.DefaultCellStyle.FormatProvider 设置为自定义格式化类的一个实例。然后，处理 CellFormatting 事件：

  void dataGridView_CellFormatting（object sender， DataGridViewCellFormattingEventArgs e）{
 if（e.CellStyle.FormatProvider is ICustomFormatter）{
 e.Value =（e.CellStyle.FormatProvider.GetFormat（typeof（ICustomFormatter））as ICustomFormatter）.Format（e.CellStyle Format，e.Value，e.CellStyle.FormatProvider）; 
 e.FormattingApplied = true; 
} 
} 
  

格式化程序类将如下所示： p>

  public class MyEnumFormatter：IFormatProvider，ICustomFormatter {
 
 public object GetFormat（Type formatType）{
 if（formatType == typeof（ICustomFormatter））
 return this; 
 else 
返回null; 
} 
 
公共字符串格式（字符串格式，对象arg，IFormatProvider formatProvider）{
 return（（NameOfEnumType）Convert.ToInt32（arg））ToString（）; 
} 
 
} 
  

So, maybe this is a bad design; I don't know. But say I have a DataTable with a column that holds int values; these values are in fact meant to represent some enum type that I have in my project.

What I'd like to do is have a DataGridView bound to this table and have the column display the name of the enum rather than the integer value "0" or "1" or whatever.

One option I considered was to do the whole normalization thing: add a table in the DataSet with the enum names in it, keyed on the enum values, and have my first table hold a reference to this table.

But this is an enum-specific idea. I would like to know if, in general, I can write my own IFormatProvider and ICustomFormatter implementation* for a given type and use that formatter to control how values are displayed in a given column of a DataGridView control (or really in any control, for that matter).

_{*This is just how I suspect it would be done, if what I'm asking is possible at all. I'm not really dead-set on using these interfaces at all.}

解决方案

You can indeed implement a custom ICustomFormatter, but due to some retardedness on the part of the DataGridView, you need to actually tell it how to apply your formatter.

First set column.DefaultCellStyle.FormatProvider to an instance of your custom formatting class. Then, handle the CellFormatting event:

void dataGridView_CellFormatting(object sender, DataGridViewCellFormattingEventArgs e) {
    if (e.CellStyle.FormatProvider is ICustomFormatter) {
        e.Value = (e.CellStyle.FormatProvider.GetFormat(typeof(ICustomFormatter)) as ICustomFormatter).Format(e.CellStyle.Format, e.Value, e.CellStyle.FormatProvider);
        e.FormattingApplied = true;
    }
}

The formatter class would look something like this:

public class MyEnumFormatter : IFormatProvider, ICustomFormatter {

    public object GetFormat(Type formatType) {
        if (formatType == typeof(ICustomFormatter))
            return this;
        else
            return null;
    }

    public string Format(string format, object arg, IFormatProvider formatProvider) {
        return ((NameOfEnumType)Convert.ToInt32(arg)).ToString();
    }

}

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