How to hide and display asp:buttons in asp.net from code behind?

问题

I am working on asp.net web application. In one Page I have two asp buttons. I want to display them in one condition otherwise I don't want to display them. So I'm trying to do the same like this. But Its not working. I can't find the reason behind it. Please tell me where is the issue.

To Hide Buttons

if (!IsPostBack)
            {
                ButtonReplaceId.Style.Add("display", "none");
                ButtonAssociateRules.Style.Add("display", "none");
            }

To display buttons

protected void ApplyAssociation(object sender, EventArgs e)
{
//Some piece of code
if(a==0)
{
ButtonAssociateRules.Style.Add("display", "block");
ButtonReplaceId.Style.Add("display", "block");
}

}

aspx for buttons

    <div style ="padding-left:400px;">
        <asp:Button ID="ButtonAssociateRules" runat="server" OnClick="AssociateMultipleRulesButtonClick"
            CssClass="search_button_in_vm_intersection" Text="Associate Multiple Rules" 
            OnClientClick="return OnClientClickAssociateRewardRuleFile();" />

        <asp:Button ID="ButtonReplaceId" runat="server" OnClick="ApplyReplaceIfRuleIntersects"
            CssClass="search_button_in_vm_intersection" Text="Replace Previous Rules" 
            OnClientClick="return OnClientClickReplaceRewardRuleFile();" />

    </div>

aspx of button for OnClick event ApplyAssociation()

<asp:UpdatePanel runat="server" UpdateMode="Conditional">
                <Triggers>
                    <asp:AsyncPostBackTrigger ControlID="Button1" EventName="Click" />
                </Triggers>
                <ContentTemplate>
                <asp:Table runat="server" CssClass="rule_file_whole" BorderWidth="0" Style="padding-top: 30px;">
                <asp:TableRow ID="MerchantRowAssociation" HorizontalAlign="Center">
                            <asp:TableCell>
                                <div style="text-align: center">
                                    <asp:Button ID="AssociationMerchant" Text="Apply Association" runat="server" OnClick="ApplyAssociation"
                                        CssClass="search_button_in_vm_associate1 " OnClientClick="return checkValidation()" />
                                </div>
                            </asp:TableCell>
                        </asp:TableRow>
                                            </asp:Table>
                </ContentTemplate>
            </asp:UpdatePanel>

回答1:

Seeing as you are using a conditional update panel, you can try either of these after putting the buttons inside an update panel.

    protected void ApplyAssociation(object sender, EventArgs e)
    {
        //Some piece of code
        if (a == 0)
        {
            ButtonAssociateRules.Style["visibility"] = "hidden";
            ButtonReplaceId.Style["visibility"] = "hidden";
            myUpdatePanel.Update();
        }
    }
    protected void ApplyAssociation(object sender, EventArgs e)
    {
        //Some piece of code
        if (a == 0)
        {
            ButtonAssociateRules.Visible = false;
            ButtonReplaceId.Visible = false;
            myUpdatePanel.Update();
        }
    }

Here's an example of your buttons inside an update panel.

<asp:UpdatePanel ID="myUpdatePanel" runat="server" UpdateMode="Conditional">
     <ContentTemplate>
          <div style="padding-left:400px;">
               <asp:Button ID="ButtonAssociateRules" runat="server" OnClick="AssociateMultipleRulesButtonClick"
                    CssClass="search_button_in_vm_intersection" Text="Associate Multiple Rules" 
                    OnClientClick="return OnClientClickAssociateRewardRuleFile();" />
               <asp:Button ID="ButtonReplaceId" runat="server" OnClick="ApplyReplaceIfRuleIntersects"
                    CssClass="search_button_in_vm_intersection" Text="Replace Previous Rules" 
                    OnClientClick="return OnClientClickReplaceRewardRuleFile();" />
          </div>
     </ContentTemplate>
</asp:UpdatePanel>

回答2:

You can simple use the Visible property of Button which is more straight forward and clean.

ButtonReplaceId.Visible = false;

If this property is false, the server control is not rendered. You should take this into account when organizing the layout of your page. If a container control is not rendered, any controls that it contains will not be rendered even if you set the Visible property of an individual control to true. In that case, the individual control returns false for the Visible property even if you have explicitly set it to true. (That is, if the Visible property of the parent control is set to false, the child control inherits that setting and the setting takes precedence over any local setting.) MSDN.

You are trying to change the state of control in ajax call that is not in current UpdatePanel. Put the buttons in the same UpdatePanel then you will be able to change the state.

回答3:

ButtonReplaceId.Visible = false;
ButtonAssociateRules.Visible = false;

来源：https://stackoverflow.com/questions/22094722/how-to-hide-and-display-aspbuttons-in-asp-net-from-code-behind

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javascript

ASP.NET

updatepanel

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