当在相关文本框中没有输入文本时，如何让 gridview 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

以下工作正常，并根据在我的文本框中输入的文本过滤我的 gridview.

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

当没有文本输入到我的文本框中时，我没有得到任何结果并且无法理解为什么.

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

我的问题

当文本框中没有输入文本时，如何让网格视图显示所有表格行?

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,'') = ''

标记

<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>

GRIDVIEW 的结果

我已经尝试并测试了这里的许多方法，但是当字符串为空时，所有方法都返回 0 结果.

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

推荐答案

查看 cancelselectonnull parameter - 默认情况下，此可防止选择参数值为null时调用select命令.将其设置为 false 后，即使文本框为空，选择 SP 仍将被调用，例如

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>

这里的 SqlDataSource 对我来说似乎有点误导，因为 TextBox.Text 在它为空时返回 String.Empty，而不是 null，因此我不希望必须为 TextBox 使用 CancelSelectOnNullParameter，但似乎我们必须.

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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