了解 ObjectDataSource 和选择参数
-
11-09-2019 - |
题
我在 GridView 控件中有一个 TemplateField,如下所示:
<asp:TemplateField ItemStyle-Width="150px">
<ItemTemplate>
<asp:DropDownList ID="ddlFields" runat="server" DataSourceID="odsOperator" DataTextField="Text" DataValueField="Value" />
<asp:HiddenField ID="hfFieldType" runat="server" Value='<%# Eval("FieldType")%>' />
</ItemTemplate>
</asp:TemplateField>
我有一个下拉列表,我想从 ObjectDataSource 填充,但对于每一行,我想传递一个选择参数,以便它填充正确的值
<asp:ObjectDataSource ID="odsOperator" runat="server" TypeName="OperatorFieldsDAO"
SelectMethod="FindByType">
<SelectParameters>
<asp:ControlParameter ControlID="hfFieldType" Type="String" Name="Type" PropertyName="Value" />
</SelectParameters>
</asp:ObjectDataSource>
我的 OperatorFieldsDAO 类是:
public class OperatorFieldsDAO
{
private List<OperatorField> OperatorFields
{
get
{
List<OperatorField> operatorFields = HttpContext.Current.Session["OperatorFields"] as List<OperatorField>;
if (operatorFields == null)
{
operatorFields = new List<OperatorField>();
operatorFields.Add(new OperatorField("string", "contains", "C"));
operatorFields.Add(new OperatorField("string", "begins with", "BW"));
operatorFields.Add(new OperatorField("string", "is equal to", "E"));
operatorFields.Add(new OperatorField("string", "is not equal to", "NE"));
operatorFields.Add(new OperatorField("string", "is less than", "L"));
operatorFields.Add(new OperatorField("string", "is greater than", "G"));
operatorFields.Add(new OperatorField("string", "is less than or equal to", "LE"));
operatorFields.Add(new OperatorField("string", "is greater than or equal to", "GE"));
operatorFields.Add(new OperatorField("string", "is from", "F"));
operatorFields.Add(new OperatorField("string", "is between", "B"));
operatorFields.Add(new OperatorField("string", "is nothing", "N"));
operatorFields.Add(new OperatorField("string", "is something", "S"));
operatorFields.Add(new OperatorField("number", "is the same as", "S"));
operatorFields.Add(new OperatorField("number", "is not the same as", "S"));
operatorFields.Add(new OperatorField("number", "is one of", "S"));
operatorFields.Add(new OperatorField("number", "is not one of", "S"));
operatorFields.Add(new OperatorField("number", "is nothing", "N"));
operatorFields.Add(new OperatorField("number", "is something", "S"));
}
return operatorFields;
}
}
public OperatorFieldsDAO() { }
[DataObjectMethod(DataObjectMethodType.Select)]
public IEnumerable<OperatorField> FindAll()
{
return this.OperatorFields;
}
[DataObjectMethod(DataObjectMethodType.Select)]
public IEnumerable<OperatorField> FindByType(String type)
{
List<OperatorField> r = new List<OperatorField>();
foreach (OperatorField f in this.OperatorFields)
if (f.Type == type)
r.Add(f);
return r;
}
}
所有这些都是为了告诉你我收到一个错误:
在 ControlParameter“Type”中找不到控件“hfFieldType”。
我究竟做错了什么?
我是否需要使用以下方式以编程方式传递所选参数 行数据绑定 方法?
解决方案
要得到这个工作我添加创建两个方法(一个用于为ObjectDataSource GridView和其他),以及从ControlParameter改变选择参数到正常参数。
我们的想法是每排它的创建时间设置参数...
protected void gvSearch_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
DropDownList d = (DropDownList)e.Row.FindControl("ddlFields");
string type = ((HiddenField)e.Row.FindControl("hfFieldType")).Value;
_type = type;
d.DataBind();
}
}
protected void odsOperator_Selecting(object sender, ObjectDataSourceSelectingEventArgs e)
{
e.InputParameters["Type"] = _type;
}
private string _type = "";
和将ObjectDataSource将是
<asp:ObjectDataSource ID="odsOperator" runat="server" TypeName="OperatorFieldsDAO"
SelectMethod="FindByType" onselecting="odsOperator_Selecting">
<SelectParameters>
<asp:Parameter Type="String" Name="Type" />
</SelectParameters>
</asp:ObjectDataSource>
我希望它能帮助任何人...
其他提示
既然你有:
<asp:HiddenField ID="hfFieldType" runat="server" .../>
在一个 TemplateField
根据您的观点,页面上可能没有、一个或多个该字段的实例。所以 hfFieldType
不会是唯一的 ID,实际上实际的 ID 将在运行时确定。
因此,您的控件参数无法找到它,因为它正在名为的控件的属性中查找其值 hfFieldType
页面上的某处。
我已经有几年没有使用 ObjectDataSource 了,但我怀疑您可能想加入 选择 事件。
的ObjectDataSource找不到所使用的控制输入,除非它是在标记附近。数据源必须是内部的包含用于输入控件的标签。 这似乎是一个作用域问题。
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