动态数据源的绑定

动态数据源的绑定

提供一种思路，可以简易地对动态数据做页面展示与绑定

以XML的形式构建控件，便于直观地控制结构

方便UI加装

便于对动态数据做表单验证

场景1：页面上的控件个数或是属性不固定，需要由数据库中的数据去决定

基本步骤：

- 1. 构建XML文本

- 2. 使用XmlTextReader生成控件

- 3. 将控件放入页面

window.cs

StackPanel sp;//容器

List<SourceModel> sourceList = GetSource();//数据源

//构建文本框集合
string xmlControls;
foreach (sourceModel in sourceList)
{
xmlControls = xmlControls +
"<c1:C1MaskedTextBox Text=\"" + sourceModel.Content + "\"/>";
}

//构建StackPanel，将文本框集合放入其中
string strXaml = "<StackPanel " +
"xmlns=\"http://schemas.microsoft.com/winfx/2006/xaml/presentation\" " +
"xmlns:x=\"http://schemas.microsoft.com/winfx/2006/xaml\" " +
"xmlns:c1=\"http://schemas.componentone.com/winfx/2006/xaml\" " +
"xmlns:basicControls=\"clr-namespace:ShenLianSystem.Common.BasicControls\" " +
"Orientation=\"Horizontal\" " +
">" +
"<StackPanel.Resources>" +
"<ResourceDictionary>" +
"<ResourceDictionary.MergedDictionaries>" +
"<ResourceDictionary Source=\"/Resources/Skins/Global.xaml\"></ResourceDictionary>" +
"</ResourceDictionary.MergedDictionaries>" +
"</ResourceDictionary>" +
"</StackPanel.Resources>" +
xmlControls +
"</StackPanel>";

//根据构建好的XML，生成控件children
StringReader strreader = new StringReader(strXaml);
System.Xml.XmlTextReader xmlreader = new System.Xml.XmlTextReader(strreader);
var children = XamlReader.Load(xmlreader) as FrameworkElement;//生成的内容

//将控件children放入容器sp
sp.Children.Clear();
sp.Children.Add(children);

场景2：在场景1的基础上，需要对数据源中的数据做update操作

一般情况下需要做绑定属性：

window.cs

xmlControls = "<c1:C1MaskedTextBox Text=\"{Binding sourceModel1.Content , Mode=TwoWay}\"/>" +
"<c1:C1MaskedTextBox Text=\"{Binding sourceModel2.Content, Mode=TwoWay}\"/>" +
"<c1:C1MaskedTextBox Text=\"{Binding sourceModel3.Content, Mode=TwoWay}\"/>" +
...;

viewmodel

SourceModel sourceModel1 { get; set; }
SourceModel sourceModel2 { get; set; }
SourceModel sourceModel3 { get; set; }
...

**但由于属性个数不确定，无法在后台声明对应的变量

用一个动态类型包装一下，将这些数目不确定的变量变成这个动态实体的属性**

window.cs

for(int i = 1; i <= sourceList.Count; i++){
xmlControls = xmlControls +
"<c1:C1MaskedTextBox Text=\"{Binding dynamicSourceModel.sourceModel" + i + ".Content, Mode=TwoWay}\"/>";
}

viewmodel

DynamicSourceModel dynamicSourceModel{ get; set; }

/// <summary>
/// 构建动态实体
/// </summary>
public void SetModel()
{
for(int i = 1; i <= sourceList.Count; i++){
dynamicSourceModel.TrySetMember("sourceModel" + i , sourceList[i]);
}
}

/// <summary>
/// 动态实体类
/// </summary>
public class DynamicSourceModel : DynamicObject
{
Dictionary<string, SourceModel> Properties = new Dictionary<string, SourceModel>();

/// <summary>
/// 赋值
/// </summary>
/// <param name="key">变量名</param>
/// <param name="value">变量值</param>
public void TrySetMember(string key, SourceModel value)
{
Properties[key] = value;
}

/// <summary>
/// 取值
/// </summary>
/// <param name="key">变量名</param>
/// <param name="result">是否有此变量</param>
/// <returns>变量值</returns>
public bool TryGetMember(string key, out SourceModel result)
{
return Properties.TryGetValue(key, out result);
}

/// <summary>
/// 按约束重写
/// </summary>
/// <param name="binder"></param>
/// <param name="result"></param>
/// <returns></returns>
public override bool TryGetMember(GetMemberBinder binder, out object result)
{
bool TryGetResult;
SourceModel model;
TryGetResult = Properties.TryGetValue(binder.Name, out model);
result = model;
return TryGetResult;
}

/// <summary>
/// 取值
/// </summary>
/// <returns>变量字典</returns>
public Dictionary<string, SourceModel> TryGetMember()
{
return Properties;
}
}