如何在数据绑定期间自定义datagridview中的数据格式
我正在寻找一种格式化DataGridViewTextBoxColumn的方法，以便在数据绑定期间格式化数据绑定的值。 例如，我有一个CompanyName属性，当数据绑定发生时，我需要从CompanyName获取前5个字母。
我可以挂钩不同的DataGridView事件（例如RowsAdded）并循环遍历所有行并执行操作，但我想找到更复杂的方法来执行此操作。 由于我已决定使用数据绑定，因此循环数据并对其进行修改有点违背了数据绑定概念。
我所追求的是如何做到如下，但添加自定义格式逻辑：
dataGridView1.Columns[colSomeDate.Index].DataPropertyName = "SomeDate"; colSomeDate.DefaultCellStyle.Format = "yyyy"; 我想我应该实现IFormatProvider，但我不太明白我应该如何实现它。
dataGridView1.Columns[companyName.Index].DataPropertyName = "CompanyName"; companyName.DefaultCellStyle.FormatProvider = new ShortText(); // ShortText should implement IFormatProvider
我不知道IFormatProvider，但DataGridViews CellFormatting事件可以帮助你吗？
private void dataGridView1_CellFormatting(object sender, DataGridViewCellFormattingEventArgs e) { if (e.ColumnIndex == 0) { e.Value = e.Value.ToString().Substring(0, 5); // apply formating here e.FormattingApplied = true; } }
http://msdn.microsoft.com/en-us/library/z1cc356h.aspx?ppud=4
向您的类中添加一个属性，为您执行子串，并绑定到该属性。
这是我为了让我的工作而做的
public class MyFormatProvider : 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) { // Check whether this is an appropriate callback if (!this.Equals(formatProvider)) return null; //if argument/ value is null we return empty string if (arg == null) return null; string resultString = arg.ToString(); //transform resultString any way you want (could do operations based on given format parameter) //return the resultant string return resultString; } }
这是我然后放入我的单元格格式处理程序
//In your datagridview, handle the cell formatting event in required cell as if (e.ColumnIndex == dgvPayments.Columns["amount"].Index) { e.Value = String.Format(new MyFormatProvider (), "{0:U}", e.Value); e.FormattingApplied = true; }
听起来像IFormatProvider正是您所需要的。 然后，您可以为不同视图的不同格式定义不同的代码。
来自Codeproject 。
public override string ToString() { return ToString("g", null); // Always support "g" as default format. } public string ToString(string format) { return ToString(format, null); } public string ToString(IFormatProvider formatProvider) { return ToString(null, formatProvider); } public string ToString(string format, IFormatProvider formatProvider) { if (format == null) format = "g"; // Set default format, which is always "g". // Continue formatting by checking format specifiers and options. }
这是我用于实现IFormattable和ICustomFormatter的示例的代码片段。
Implements IFormattable Implements ICustomFormatter Public Function Format(ByVal formatExpression As String, ByVal arg As Object, ByVal formatProvider As System.IFormatProvider) As String Implements System.ICustomFormatter.Format 'type is currently ignored ' if type is international then "USPS" should result in international address ' if type is international then "US" should result in international address ' and so on ' '.NET Framework Class Library 'IFormattable Interface 'Remarks - A class that implements IFormattable must support the "G" (general) formatting code. Besides the "G" code, the class can define the list of formatting codes that it supports. 'is G and g the same? ' yes for numeric ' no for date/time 'Standard Numeric Format Strings ' G or g - both are the same 'Standard DateTime Format Strings ' g - General date/time pattern (short time) ' G - General date/time pattern (long time) If Len(formatExpression) = 0 Then Return String.Format("{0}", arg) End If 'usps - standardized 'us - address less country 'international - all address lines If formatExpression.Equals("g") Then 'general formatting code ' as per documentation Return GatherAddress(_line1, _line2, _city, _state, _zip, _country, _type, AddressFormat.StandardUS) ElseIf formatExpression.Equals("G") Then 'general formatting code ' as per documentation Return GatherAddress(_line1, _line2, _city, _state, _zip, _country, _type, AddressFormat.Standardized) ElseIf formatExpression.ToUpper.Equals("USPS") Then Return GatherAddress(_line1, _line2, _city, _state, _zip, _country, _type, AddressFormat.Standardized) ElseIf formatExpression.ToUpper.Equals("US") Then Return GatherAddress(_line1, _line2, _city, _state, _zip, _country, _type, AddressFormat.StandardUS) ElseIf formatExpression.ToUpper.Equals("INTERNATIONAL") Then Return GatherAddress(_line1, _line2, _city, _state, _zip, _country, _type, AddressFormat.International) Else Return MyBase.ToString() End If End Function Public Overloads Function ToString(ByVal format As String, ByVal formatProvider As System.IFormatProvider) As String Implements System.IFormattable.ToString Return Me.Format(format, Nothing, formatProvider) End Function
你总是可以从你的aspx页面调用这样的自定义格式函数：
然后在该页面的代码后面：
protected string GetImagePath(object abbr){ return string.Format("{0}{1}.gif", Constants.URLs.PLATFORM_LOGOS, abbr.ToString());}
我通常使用ValueConverters来实现这种行为。
就像是：
在control / page的resources节点中，您需要添加以下内容：
CompanyNameShortenerConverter应该实现IValueConverter，您可以添加逻辑以“缩短”在“转换”方法中传入的公司名称。
这使格式/ UI逻辑与业务逻辑分离（即不需要添加缩短名称的“辅助属性”）。