如何在没有文本输入到依赖文本框中时使用gridview来显示所有表格行？ [英] How to get a gridview to show all table rows when no text is entered in a dependent textbox?

问题描述

下面的工作正常，并基于在我的文本框中输入的文本过滤我的gridview。

当没有文本输入到我的文本框中时，我得不到结果并且无法理解为什么。

我的问题

如何让gridview显示所有表格行中没有文本输入到文本框中？

MSSQL

  @Search nvarchar（50）
 
 SELECT [table]。[column] 
 FROM [table] 
 WHERE [ table]。[column] LIKE'％'+ @Search +'％'OR COALESCE（@Search，''）=''
  

MARKUP

 < asp：TextBox ID =txtSearch RunAt =ServerText =/> 
 
< asp：SqlDataSource ID =sqlSearchRunAt =ServerSelectCommand =spSearchSelectCommandType =StoredProcedure> 
< SelectParameters> 
< asp：ControlParameter Type =StringName =SearchControlID =txtSearchPropertyName =Text/> 
< / SelectParameters> 
< / asp：SqlDataSource> 
  

GRIDVIEW结果

我试过并测试了很多在这里找到的方法，但是当字符串为空时，所有返回0的结果都是。 在取消选择所有空参数 - 默认情况下，这防止 select参数的值为null时调用select命令。将它设置为 false 后，即使文本框为空，选择的SP仍然会被调用，例如，

 < asp：SqlDataSource ID =sqlSearchRunAt =服务器
 CancelSelectOnNullParameter =false.. > 
< / asp：SqlDataSource> 
  

SqlDataSource在这里似乎有点误导我，因为TextBox.Text在空时返回String.Empty ，不为null，因此我不希望为TextBox混淆CancelSelectOnNullParameter，但似乎我们必须。

The below works correctly and filters my gridview based on the text entered in my textbox.

When no text is entered into my textbox I get no results and cannot understand why.

MY QUESTION

How to get a gridview to show all table rows when no text is entered in the textbox?

MSSQL

@Search nvarchar(50)

SELECT  [table].[column]
FROM    [table]
WHERE   [table].[column] LIKE '%' + @Search + '%' OR COALESCE(@Search,'') = ''

MARKUP

<asp:TextBox ID="txtSearch" RunAt="Server" Text=""/>

<asp:SqlDataSource ID="sqlSearch" RunAt="Server" SelectCommand="spSearch" SelectCommandType="StoredProcedure">
  <SelectParameters>
    <asp:ControlParameter Type="String" Name="Search" ControlID="txtSearch" PropertyName="Text"/>
  </SelectParameters> 
</asp:SqlDataSource>

RESULTS TO GRIDVIEW

I have tried and tested many methods found on here however all return 0 results when string is empty.

解决方案

Look at CancelSelectOnNullParameter - by default, this prevents the select command from being called when a select parameter's value is null. After setting it to false, the select SP will then still get called even if the text box is empty, e.g.

<asp:SqlDataSource ID="sqlSearch" RunAt="Server" 
    CancelSelectOnNullParameter="false" ...>
</asp:SqlDataSource>

The SqlDataSource seems a bit misleading to me here, because TextBox.Text returns String.Empty when it's empty, not null, therefore I wouldn't expect to have to mess with CancelSelectOnNullParameter for a TextBox, but it seems we have to.

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