我希望这是一个简单的问题。我有一个绑定到sqldatasource的gridview控件。
首先，相关代码：
<asp:DropDownList ID="cboCustomerID" runat="server"
DataSourceID="DataSourceCustomer" DataTextField="CustomerName" DataValueField="CustomerID">
</asp:DropDownList>
<asp:DropDownList ID="cboStaffID" runat="server"
DataSourceID="DataSourceStaff" DataTextField="StaffFullName" DataValueField="StaffID">
</asp:DropDownList>
<div><gcctl:MyCheckBox ID="chkShowClosed" Text="Show Closed Jobs?" Checked="false" AutoPostBack="true" runat="server" /></div>
<div><asp:Button ID="btnSearch" runat="server" OnClick="btnSearch_Click" Text="Search" /></div>
<div id="customersearchresults" class="searchresults">
<asp:SqlDataSource id="gvJobsDataSource" runat="server" ConnectionString="<%$ ConnectionStrings:GeekCommandConnString %>"
SelectCommand="SELECT j.JobID, j.JobName, s.JobStatus, jal.[JobAssignmentsFullList]
FROM (SELECT * FROM [dbo].[Jobs] WHERE ((NULLIF(@CustomerSearch,'') IS NOT NULL AND CustomerID = @CustomerSearch) OR (NULLIF(@CustomerSearch,'') IS NULL))) j
INNER JOIN (SELECT * FROM [list].[JobStatuses] WHERE ((@ShowClosed = 0 AND IsStatusOpen = 1) OR (@ShowClosed = 1)) AND IsActive = 1) s ON j.JobStatusID = s.JobStatusID
LEFT JOIN (SELECT * FROM [dbo].[JobAssignments] WHERE ((NULLIF(@StaffSearch,'') IS NOT NULL AND StaffID = @StaffSearch) OR (NULLIF(@StaffSearch,'') IS NULL))) ja ON j.JobID = ja.JobID
LEFT JOIN [dbo].[udv_JobAssignmentsCommaDelimited] jal ON j.JobID = jal.JobID
">
<SelectParameters>
<asp:Parameter Name="CustomerSearch" Type="Int32" />
<asp:Parameter Name="StaffSearch" Type="Int32" />
<asp:Parameter Name="ShowClosed" Type="Boolean" />
</SelectParameters>
</asp:SqlDataSource>
<asp:GridView ID="gvJobs" runat="server" AllowSorting="True"
AutoGenerateColumns="False"
DataKeyNames="JobID"
DataSourceID="gvJobsDataSource"
AutoGenerateDeleteButton="False"
AutoGenerateEditButton="False"
AutoGenerateSelectButton="False"
CssClass="searchresultsgrid"
AllowPaging="True" PageSize="50"
OnRowCommand="gvJobs_RowCommand"
EmptyDataText="No matching jobs on record." >
<Columns>
<asp:templatefield>
<itemtemplate>
<asp:linkbutton id="btnEdit" runat="server" CommandName="JobEdit" OnClientClick="PageForm.target ='_blank';" text="View/Edit" />
</itemtemplate>
</asp:templatefield>
<asp:BoundField DataField="JobID" HeaderText="ID" InsertVisible="false" ReadOnly="true" Visible="false" SortExpression="JobID" />
<asp:templateField HeaderText="Job Name" SortExpression="JobName">
<ItemTemplate><%# Eval("JobName") %></ItemTemplate>
</asp:templateField>
<asp:templateField HeaderText="Assigned to" SortExpression="JobAssignmentsFullList">
<ItemTemplate><%# Eval("JobAssignmentsFullList") %></ItemTemplate>
</asp:templateField>
</Columns>
</asp:GridView>
</div>
<asp:SqlDataSource ID="DataSourceCustomer" runat="server"
ConnectionString="<%$ ConnectionStrings:GeekCommandConnString %>"
SelectCommand="SELECT NULL AS [CustomerID]
, NULL AS [CustomerName]
UNION SELECT [CustomerID]
,[CustomerName]
FROM [GeekCommand].[dbo].[Customers]
WHERE ((@ShowInactive = 0 AND IsActive = 1) OR (@ShowInactive = 1))
ORDER BY CustomerName">
<SelectParameters>
<asp:ControlParameter Name="ShowInactive" Type="Boolean" ControlID="chkCustomersShowInactive" PropertyName="Checked" />
</SelectParameters>
</asp:SqlDataSource>
<asp:SqlDataSource ID="DataSourceStaff" runat="server"
ConnectionString="<%$ ConnectionStrings:GeekCommandConnString %>"
SelectCommand="SELECT NULL AS [StaffID]
, NULL AS [StaffFullName]
UNION SELECT [StaffID]
,COALESCE([FirstName], [Nickname], '') + ' ' + COALESCE([LastName], '') AS StaffFullName
FROM [GeekCommand].[dbo].[Staff]
WHERE ((@ShowInactive = 0 AND IsActive = 1) OR (@ShowInactive = 1))
ORDER BY StaffFullName">
<SelectParameters>
<asp:ControlParameter Name="ShowInactive" Type="Boolean" ControlID="chkStaffShowInactive" PropertyName="Checked" />
</SelectParameters>
</asp:SqlDataSource>
相关的aspx.cs代码：
int? iCustomerID;
int? iStaffID;
//--------
protected void SetIDs()
{
this.iCustomerID = null;
this.iStaffID = null;
if (Request.QueryString["customerid"] != null) //new customer
{
try
{
this.iCustomerID = Convert.ToInt32(Request.QueryString["customerid"]);
}
catch { }
}
if (Request.QueryString["staffid"] != null) //new customer
{
try
{
this.iStaffID = Convert.ToInt32(Request.QueryString["staffid"]);
}
catch { }
}
if (iCustomerID != null)
{
cboCustomerID.SelectedValue = iCustomerID.ToString();
}
if (iStaffID != null)
{
cboStaffID.SelectedValue = iStaffID.ToString();
}
}
//--------
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
SetIDs();
}
}
//--------
protected void btnSearch_Click(object sender, EventArgs e)
{
gvJobsDataSource.SelectParameters["CustomerSearch"].DefaultValue = cboCustomerID.SelectedValue.ToString();
gvJobsDataSource.SelectParameters["StaffSearch"].DefaultValue = cboStaffID.SelectedValue.ToString();
gvJobsDataSource.SelectParameters["ShowClosed"].DefaultValue = chkShowClosed.Checked.ToString();
gvJobs.DataBind();
}
当我在SSMS中运行以下内容时，我得到了2行，我应该这样做：
DECLARE @CustomerSearch int, @StaffSearch int, @ShowClosed bit
SELECT @CustomerSearch = 2331, @StaffSearch = '', @ShowClosed = CAST(0 AS bit)
SELECT j.JobID, j.JobName, s.JobStatus, jal.[JobAssignmentsFullList]
FROM (SELECT * FROM [dbo].[Jobs] WHERE ((NULLIF(@CustomerSearch,'') IS NOT NULL AND CustomerID = @CustomerSearch) OR (NULLIF(@CustomerSearch,'') IS NULL))) j
INNER JOIN (SELECT * FROM [list].[JobStatuses] WHERE ((@ShowClosed = 0 AND IsStatusOpen = 1) OR (@ShowClosed = 1)) AND IsActive = 1) s ON j.JobStatusID = s.JobStatusID
LEFT JOIN (SELECT * FROM [dbo].[JobAssignments] WHERE ((NULLIF(@StaffSearch,'') IS NOT NULL AND StaffID = @StaffSearch) OR (NULLIF(@StaffSearch,'') IS NULL))) ja ON j.JobID = ja.JobID
LEFT JOIN [dbo].[udv_JobAssignmentsCommaDelimited] jal ON j.JobID = jal.JobID
但是当我在调试模式下选择一个客户（特别是id为2331的客户）并逐步执行btnSearch_Click代码时，cboCustomerID.SelectedValue =“2331”，cboStaffID.SelectedValue =“”，chkShowClosed.Checked = false（全部其中是正确的）...但是当我跳过databind命令时没有任何反应。 gridview继续显示“记录中没有匹配的作业。”
我觉得我错过了一些非常明显的东西，但我不能为我的生活找出它是什么。
更新：好的。这是有趣的。显然，查询永远不会被发送到SQL Server。我刚刚以跟踪模式启动SQL Server，重新加载了aspx页面并进行了搜索，虽然日志中有两个下拉列表后面的查询，但gridview后面的查询却不存在。
更新＃2：我已使用以下内容替换了选择参数：
<asp:ControlParameter Name="CustomerSearch" ControlID="cboCustomerID" PropertyName ="SelectedValue" />
<asp:ControlParameter Name="StaffSearch" ControlID="cboStaffID" PropertyName ="SelectedValue" />
<asp:ControlParameter Name="ShowClosed" Type="Boolean" ControlID="chkShowClosed" PropertyName="Checked" />
...并删除了btnSearch_Click事件中的额外代码，因此该代码中唯一的一行是：
protected void btnSearch_Click(object sender, EventArgs e)
{
gvJobs.DataBind();
}
......没有变化。单击搜索按钮时仍然没有任何反应。
答案 0 :(得分：0)
耶！找到答案： https://forums.asp.net/t/1243253.aspx?Gridview+Databind+Not+Working
问题是gridviews有一个属性：CancelSelectOnNullParameter，默认情况下为true。由于在我进行搜索时，至少有一个下拉列表几乎总是为空，因此当我点击搜索按钮时没有发生任何事情。当我将CancelSelectOnNullParameter =“false”添加到gridview控件时，它修复了问题。
（半相关说明）我还在ControlParameters中添加了以下内容：ConvertEmptyStringToNull =“true”