c# - 使用 LinqDataSource 和 Formview 自定义分页

Question

我正在尝试使用 LinqDataSource 的Selecting事件来过滤 FormView 的数据，但是我似乎无法让它正确分页。我只能设法在 FormView 中显示一条记录，但分页控件不显示。Selecting我在 LinqDataSource事件中有以下代码：

e.Arguments.StartRowIndex = 0;
e.Arguments.MaximumRows = 1;

var result = db.Personnels.AsQueryable();

if (!String.IsNullOrEmpty(txtFirstName.Text))
{
    result = result.Where(r => r.First_Name.Contains(txtFirstName.Text));
}

if (!String.IsNullOrEmpty(txtLastName.Text))
{
    result = result.Where(r => r.Last_Name.Contains(txtLastName.Text));
}

e.Arguments.TotalRowCount = result.Count();

e.Result = result.Skip(fvMain.PageIndex).Take(1);

如上所述，此代码有效，但是仅显示一条记录，并且分页控件未显示在 FormView 上。我也尝试e.Result使用以下内容进行修改，但出现Object reference not set to an instance of an object.异常：

e.Result = result;

使用 LinqDataSource 的选择事件对 FormView 进行分页的正确方法是什么？

编辑 1

根据要求，这里是 FormView 和 LinqDataSource 的标记：

<asp:FormView ID="fvMain" runat="server" CssClass="full" 
    DataKeyNames="Worker_ID" DataSourceID="ldsMain" DefaultMode="Edit" 
    AllowPaging="True" onitemupdating="fvMain_ItemUpdating">
    <EditItemTemplate>
        <table class="pad5 full">
            <tr>
                <td class="field-name" style="width: 100px">Worker ID:</td>
                <td style="width: 80px"><asp:TextBox ID="txtWorkerID" runat="server" Text='<%#Eval("Worker_ID") %>' ReadOnly="true" style="width: 75px" /></td>
                <td class="right"><input type="button" value="Injuries/LTA/WCB for this Person" onclick="openModalColorbox('Injuries.aspx?id='+$('#plcMain_fvMain_txtWorkerID').val(), 'Injuries')" /></td>
            </tr>
        </table>
        <table class="pad5 full">
            <tr>
                <td class="field-name">Type Of Person:</td>
                <td colspan="3">
                    <cc1:DataBindDropDownList ID="cboTypeOfPerson" runat="server" 
                        AppendDataBoundItems="True" DataSourceID="ldsPersonTypes" 
                        DataTextField="Type_of_Person" DataValueField="Type_of_Person" 
                        SelectedValue='<%#Bind("Type_Of_Person") %>'>
                        <asp:ListItem Text="" Value="" />
                    </cc1:DataBindDropDownList>
                    <asp:LinqDataSource ID="ldsPersonTypes" runat="server" 
                        ContextTypeName="PRIDE.PRIDEDataContext" EntityTypeName="" 
                        OrderBy="Type_of_Person" TableName="Personnel_Types">
                    </asp:LinqDataSource>
                </td>
            </tr>
            <tr>
                <td class="field-name">Employee Number:</td>
                <td><asp:TextBox ID="txtEmployeeNumber" runat="server" Text='<%#Bind("Employee_Number") %>' /></td>
                <td class="field-name">SIN:</td>
                <td><asp:TextBox ID="txtSIN" runat="server" Text='<%#Bind("SIN") %>' /></td>
            </tr>
            <tr>
                <td class="field-name">Last Name:</td>
                <td><asp:TextBox ID="txtLastName" runat="server" Text='<%#Bind("Last_Name") %>' /></td>
                <td class="field-name">Previous Last Name:</td>
                <td><asp:TextBox ID="txtPreviousLastName" runat="server" Text='<%#Bind("Previous_Last_Name") %>' /></td>
            </tr>
            <tr>
                <td class="field-name">First Name:</td>
                <td><asp:TextBox ID="txtFirstName" runat="server" Text='<%#Bind("First_Name") %>' /></td>
                <td class="field-name">Marital Status:</td>
                <td>
                    <cc1:DataBindDropDownList ID="DropDownList1" runat="server" 
                        AppendDataBoundItems="True" SelectedValue='<%# Bind("Marital_Status") %>' 
                        DataSourceID="ldsMaritalStatuses" DataTextField="Marital_Status" 
                        DataValueField="Marital_Status">
                        <asp:ListItem Text="" Value="" />
                    </cc1:DataBindDropDownList>
                    <asp:LinqDataSource ID="ldsMaritalStatuses" runat="server" 
                        ContextTypeName="PRIDE.PRIDEDataContext" EntityTypeName="" 
                        OrderBy="Marital_Status" TableName="List____Employee__Marital_Status">
                    </asp:LinqDataSource>
                </td>
            </tr>
            <tr>
                <td class="field-name">Division:</td>
                <td>
                    <cc1:DataBindDropDownList ID="cboDivision" runat="server" 
                        AppendDataBoundItems="True" SelectedValue='<%# Bind("Division") %>' 
                        DataSourceID="ldsDivisions" DataTextField="Division" 
                        DataValueField="Division">
                        <asp:ListItem Text="" Value="" />
                    </cc1:DataBindDropDownList>
                    <asp:LinqDataSource ID="ldsDivisions" runat="server" 
                        ContextTypeName="PRIDE.PRIDEDataContext" EntityTypeName="" GroupBy="Division" 
                        OrderBy="Division" Select="new (key as Division, it as Areas)" 
                        TableName="Areas">
                    </asp:LinqDataSource>
                </td>
                <td class="field-name">DOB:</td>
                <td>
                    <asp:TextBox ID="txtDOB" runat="server" Text='<%#Bind("DOB", "{0:dd MMM yyyy}") %>' />
                    <asp:CalendarExtender ID="CalendarExtender1" runat="server" TargetControlID="txtDOB" Format="dd MMM yyyy" />
                </td>
            </tr>
            <tr>
                <td class="field-name">Department:</td>
                <td>
                    <cc1:DataBindDropDownList ID="cboDepartment" runat="server" 
                        AppendDataBoundItems="True" SelectedValue='<%# Bind("Department") %>' 
                        DataSourceID="ldsDepartments" DataTextField="Department" 
                        DataValueField="Department">
                        <asp:ListItem Text="" Value="" />
                    </cc1:DataBindDropDownList>
                    <asp:LinqDataSource ID="ldsDepartments" runat="server" 
                        ContextTypeName="PRIDE.PRIDEDataContext" EntityTypeName="" GroupBy="Department" 
                        OrderBy="Department" Select="new (key as Department, it as Areas)" 
                        TableName="Areas">
                    </asp:LinqDataSource>
                </td>
                <td class="field-name">Terminated:</td>
                <td>
                    <cc1:DataBindDropDownList ID="cboTerminated" runat="server" 
                        SelectedValue='<%# Bind("Terminated") %>'>
                        <asp:ListItem Text="" Value="" />
                        <asp:ListItem Text="Yes" Value="Yes" />
                        <asp:ListItem Text="No" Value="No" />
                    </cc1:DataBindDropDownList>
                </td>
            </tr>
            <tr>
                <td class="field-name">Occupation:</td>
                <td>
                    <cc1:DataBindDropDownList ID="cboOccupation" runat="server" 
                        SelectedValue='<%# Bind("Occupation") %>' AppendDataBoundItems="True" 
                        DataSourceID="ldsOccupations" DataTextField="Occupation" 
                        DataValueField="Occupation">
                        <asp:ListItem Text="" Value="" />
                    </cc1:DataBindDropDownList>

                    <asp:LinqDataSource ID="ldsOccupations" runat="server" 
                        ContextTypeName="PRIDE.PRIDEDataContext" EntityTypeName="" OrderBy="Occupation" 
                        TableName="List____Employee__Occupations">
                    </asp:LinqDataSource>
                </td>
                <td class="field-name">Team:</td>
                <td>
                    <cc1:DataBindDropDownList ID="cboTeam" runat="server" 
                        SelectedValue='<%# Bind("Shift") %>' AppendDataBoundItems="True" 
                        DataSourceID="ldsShifts" DataTextField="Shift" 
                        DataValueField="Shift">
                        <asp:ListItem Text="" Value="" />
                    </cc1:DataBindDropDownList>

                    <asp:LinqDataSource ID="ldsShifts" runat="server" 
                        ContextTypeName="PRIDE.PRIDEDataContext" EntityTypeName="" OrderBy="Shift" 
                        TableName="List____Employee__Shifts">
                    </asp:LinqDataSource>
                </td>
            </tr>
            <tr>
                <td class="field-name">Lock Number:</td>
                <td><asp:TextBox ID="txtLockNumber" runat="server" Text='<%#Bind("Lock_Number") %>' /></td>
                <td class="field-name">Address:</td>
                <td><asp:TextBox ID="txtAddress" runat="server" Text='<%#Bind("Address") %>' /></td>
            </tr>
            <tr>
                <td class="field-name">City:</td>
                <td><asp:TextBox ID="txtCity" runat="server" Text='<%#Bind("City") %>' /></td>
                <td class="field-name">Company:</td>
                <td><asp:TextBox ID="txtCompany" runat="server" Text='<%#Bind("Company") %>' /></td>
            </tr>
            <tr>
                <td class="field-name">Province:</td>
                <td><asp:TextBox ID="txtProvince" runat="server" Text='<%#Bind("Province") %>' /></td>
                <td class="field-name">Company Contact:</td>
                <td><asp:TextBox ID="txtCompanyContact" runat="server" Text='<%#Bind("Company_Contact") %>' /></td>
            </tr>
            <tr>
                <td class="field-name">Postal:</td>
                <td><asp:TextBox ID="txtPostal" runat="server" Text='<%#Bind("Postal") %>' /></td>
                <td class="field-name">Phone:</td>
                <td><asp:TextBox ID="txtPhone" runat="server" Text='<%#Bind("Phone") %>' /></td>
            </tr>
            <tr>
                <td class="field-name">HCN:</td>
                <td><asp:TextBox ID="txtHCN" runat="server" Text='<%#Bind("HCN") %>' /></td>
                <td class="field-name">HCN Province:</td>
                <td><asp:TextBox ID="txtHCNProvince" runat="server" Text='<%#Bind("HCN_Province") %>' /></td>
            </tr>
            <tr>
                <td class="field-name">Comments:</td>
                <td colspan="3">
                    <asp:TextBox ID="txtComments" runat="server" Text='<%#Bind("Comments") %>' TextMode="MultiLine" Rows="3" />
                </td>
            </tr>
        </table>

        <h2>H.R.I.S.</h2>
        <table class="pad5 full">
            <tr>
                <td class="field-name">NOK Name:</td>
                <td><asp:TextBox ID="txtNOKName" runat="server" Text='<%#Bind("NOK_Name") %>' /></td>
                <td class="field-name">NOK Relation:</td>
                <td>
                    <cc1:DataBindDropDownList ID="cboNOKRelation" runat="server" 
                        SelectedValue='<%# Bind("NOK_Relation") %>' AppendDataBoundItems="True" 
                        DataSourceID="ldsNOKRelations" DataTextField="Relationship" 
                        DataValueField="Relationship">
                        <asp:ListItem Text="" Value="" />
                    </cc1:DataBindDropDownList>

                    <asp:LinqDataSource ID="ldsNOKRelations" runat="server" 
                        ContextTypeName="PRIDE.PRIDEDataContext" EntityTypeName="" 
                        OrderBy="Relationship" TableName="List____Employee__Relations">
                    </asp:LinqDataSource>
                </td>
            </tr>
            <tr>
                <td class="field-name">NOK Address:</td>
                <td><asp:TextBox ID="txtNOKAddress" runat="server" Text='<%#Bind("NOK_Address") %>' /></td>
                <td class="field-name">NOK City:</td>
                <td><asp:TextBox ID="txtNOKCity" runat="server" Text='<%#Bind("NOK_City") %>' /></td>
            </tr>
            <tr>
                <td class="field-name">NOK Province:</td>
                <td><asp:TextBox ID="txtNOKProvince" runat="server" Text='<%#Bind("NOK_Province") %>' /></td>
                <td class="field-name">NOK Postal:</td>
                <td><asp:TextBox ID="txtNOKPostal" runat="server" Text='<%#Bind("NOK_Postal") %>' /></td>
            </tr>
            <tr>
                <td class="field-name">NOK Phone:</td>
                <td><asp:TextBox ID="txtNOKPhone" runat="server" Text='<%#Bind("NOK_Phone") %>' /></td>
            </tr>
        </table>

        <div class="center">
            <asp:Button ID="btnSave" runat="server" Text="Save Changes" 
                onclick="btnSave_Click" />
        </div>
    </EditItemTemplate>
    <PagerSettings Mode="NextPreviousFirstLast" 
                FirstPageText="&amp;lt;&amp;lt; First" LastPageText="Last &amp;gt;&amp;gt;" 
                NextPageText="Next &amp;gt;" PreviousPageText="&amp;lt; Previous" 
                Position="TopAndBottom" />
            <PagerStyle CssClass="pager" />
</asp:FormView>
<asp:LinqDataSource ID="ldsMain" runat="server" 
    ContextTypeName="PRIDE.PRIDEDataContext" EnableDelete="True" 
    EnableInsert="True" EnableUpdate="True" EntityTypeName="" 
    TableName="Personnels" onselecting="ldsMain_Selecting">
    <UpdateParameters>
        <asp:Parameter ConvertEmptyStringToNull="true" Name="Employee_Number" />
    </UpdateParameters>
    <InsertParameters>
        <asp:Parameter ConvertEmptyStringToNull="true" Name="Employee_Number" />
    </InsertParameters>
</asp:LinqDataSource>

score 0 · Accepted Answer

从MSDN中我们可以看到，默认情况下设置为的AutoPage属性。从文档：LinqDataSourcetrue

当 AutoPage 属性设置为 true 时，LinqDataSource 控件仅检索数据绑定控件中一页的足够记录。它使用Skip<TSource>andTake<TSource>方法来检索当前页面的记录。

所有这一切的结果是您需要更改一些内容才能使分页正常工作。

目前您正在设置e.Arguments.StartRowIndex = 0;. 您不需要每次都这样做，因为它会干扰分页。
做e.Result = result.Skip(fvMain.PageIndex).Take(1);也没有必要。应该e.Result = result;没问题。

我认为这两件事的结合导致了你的问题。但是，我们现在需要处理您的某个过滤器启动的情况。

第一个问题是我们需要将先前应用的过滤器持久化到 ViewState 中，否则我们将无法判断何时刚刚应用了过滤器以及何时应用了现有过滤器。

灵感来自在对连接到 GridView 的 linqdatasource 应用过滤器后，单击编辑将我带回旧数据，向您的页面添加一个属性（您将需要另一个属性作为姓氏）：

public string FirstNameFilter 
{
    get
    {
        return (string)this.ViewState["FirstNameFilter"] ?? string.Empty;
    }

    set
    {
        this.ViewState["FirstNameFilter"] = value;
    }
}

然后在您的Selecting事件处理程序中，运行以下代码：

var result = db.Personnels.AsQueryable();

if (!string.IsNullOrEmpty(txtFirstName.Text))
{
    if (this.FirstNameFilter != txtFirstName.Text)
    {
        this.FirstNameFilter = txtFirstName.Text;
        e.Arguments.StartRowIndex = 0;
    }

    if (!string.IsNullOrEmpty(this.FirstNameFilter))
    {
        result = result.Where(r => r.First_Name.Contains(txtFirstName.Text));
    }
}

if (!string.IsNullOrEmpty(txtLastName.Text))
{
    if (this.LastNameFilter != txtLastName.Text)
    {
        this.LastNameFilter = txtLastName.Text;
        e.Arguments.StartRowIndex = 0;
    }

    if (!string.IsNullOrEmpty(this.LastNameFilter))
    {
        result = result.Where(r => r.First_Name.Contains(txtLastName.Text));
    }
}

e.Arguments.TotalRowCount = result.Count();

e.Result = result;

score 0 · Accepted Answer

我不知道为什么，但我的问题是通过将读取的行更改e.Result = result...为e.Result = result.Skip(0). 之后，分页工作完美。

c# - 使用 LinqDataSource 和 Formview 自定义分页

2 回答 2

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