As mentioned earlier in this chapter, the viewer control should only be used to modify the display properties of the viewer and shouldn’t be relied upon to make report changes. However, the viewer does have this functionality built into it, so we’ll cover it here so that you know how to use it if the need arises.<\/p>\n
Programming with the viewer has some similarities to programming with the ReportDocument class, but there are differences. From a high level, the viewer is similar because you have to get a reference to the parameter object and assign a value to its CurrentValues collection. From an implementation standpoint, the viewer is different because the names of the parameter classes are different.<\/p>\n
The viewer is also different in how you assign the current\/default value collection. It requires that you override the existing values collection with the new values collection. The ReportDocument class has you call the ApplyCurrentValue() method to do this.<\/p>\n
The viewer uses the ParameterFields collection to manage the properties of each parameter in a report. The ParameterFields collection manages the ParameterField object.<\/p>\n
Programming with the CrystalReportViewer consists of 8 steps:<\/p>\n
Listing 16-8 illustrates these steps. It creates a parameter that is a range value and assigns it to the CurrentValues collection. The in-line comments explain the steps that are taking place.<\/p>\n Listing 16-8. Use the viewer to modify a range parameter.<\/b> Programming the CrystalReportViewer Control As mentioned earlier in this chapter, the viewer control should only be used to modify the display properties of the viewer and shouldn’t be relied upon to make report changes. However, the viewer does have this functionality built into it, so we’ll cover it here so that you know how to […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[41,40],"tags":[],"class_list":["post-813","post","type-post","status-publish","format-standard","hentry","category-chapter-16-modifying-formulas-and-parameters","category-crystal-reportsnet-2008","entry"],"_links":{"self":[{"href":"http:\/\/www.crystalreportsonlinetraining.com\/training\/wp-json\/wp\/v2\/posts\/813","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.crystalreportsonlinetraining.com\/training\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.crystalreportsonlinetraining.com\/training\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.crystalreportsonlinetraining.com\/training\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.crystalreportsonlinetraining.com\/training\/wp-json\/wp\/v2\/comments?post=813"}],"version-history":[{"count":1,"href":"http:\/\/www.crystalreportsonlinetraining.com\/training\/wp-json\/wp\/v2\/posts\/813\/revisions"}],"predecessor-version":[{"id":1795,"href":"http:\/\/www.crystalreportsonlinetraining.com\/training\/wp-json\/wp\/v2\/posts\/813\/revisions\/1795"}],"wp:attachment":[{"href":"http:\/\/www.crystalreportsonlinetraining.com\/training\/wp-json\/wp\/v2\/media?parent=813"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.crystalreportsonlinetraining.com\/training\/wp-json\/wp\/v2\/categories?post=813"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.crystalreportsonlinetraining.com\/training\/wp-json\/wp\/v2\/tags?post=813"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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\n [VB.NET]<\/b>
\n Dim myParameterValues as New CrystalDecisions.Shared.ParameterValues<\/code>
\n Dim myParameterField As CrystalDecisions.Shared.ParameterField<\/code>
\n Dim myParameterRangeValue As CrystalDecisions.Shared.ParameterRangeValue<\/code>
\n 'Step 1: Assign the report object to the viewer<\/code>
\n CrystalReportViewer1.ReportSource = Server.MapPath(\"Invoice.rpt\")<\/code>
\n 'Step 2: Reference the ParameterField object<\/code>
\n myParameterField = CrystalReportViewer1.ParameterFieldInfo(\"DateRange\")<\/code>
\n 'Step 3: Create a ParameterValue object.<\/code>
\n myParameterRangeValue = New CrystalDecisions.Shared.ParameterRangeValue<\/code>
\n 'Step 4: Assign a value to the object<\/code>
\n myParameterRangeValue.StartValue = DateTime.Parse(\"1\/4\/1997\")<\/code>
\n myParameterRangeValue.EndValue = DateTime.Parse(\"2\/2\/1997\")<\/code>
\n 'Step 5: Add the ParameterValue object to the values collection<\/code>
\n myParameterValues.Add(myParameterRangeValue)<\/code>
\n 'Step 6: Override the CurrentValues collection with the new values collection<\/code>
\n myParameterField.CurrentValues = myParameterRangeValue<\/code>
\n [C#]<\/b>
\n CrystalDecisions.Shared.ParameterFields ParameterFields;<\/code>
\n CrystalDecisions.Shared.IParameterField ParameterField;<\/code>
\n CrystalDecisions.Shared.ParameterRangeValue ParameterRangeValue;<\/code>
\n \/\/Step 1: Assign the report object to the viewer<\/code>
\n CrystalReportViewer1.ReportSource = Server.MapPath(\"Invoice.rpt\");<\/code>
\n \/\/Step 2: Reference the ParameterField object<\/code>
\n ParameterFields = crystalReportViewer1.ParameterFieldInfo[\"DateRange\"];<\/code>
\n \/\/Step 3: Create a ParameterValue object<\/code>
\n ParameterRangeValue = new CrystalDecisions.Shared.ParameterRangeValue();<\/code>
\n \/\/Step 4: Assign a value to the object<\/code>
\n ParameterRangeValue.StartValue = DateTime.Parse(\"1\/4\/1997\");<\/code>
\n ParameterRangeValue.EndValue = DateTime.Parse(\"1\/20\/1997\");<\/code>
\n \/\/Step 6: Override the CurrentValues collection with the new values collection<\/code>
\n ParameterField.CurrentValues = ParameterRangeValue;<\/code><\/p>\n","protected":false},"excerpt":{"rendered":"