This example shows how to set variable value from code. First, load scripts:

@using Stimulsoft.Base
@using Stimulsoft.Report
@using Stimulsoft.Report.Blazor

Next, create buttons:

<div align="center">
    <input type="text" @bind="newValueInput" />
    <button class="alert" @onclick="SetVariable">Set variable</button>
</div>

Then, add report viewer:

<div align="center">
    <StiBlazorViewer Report="@Report" />
</div>

After that, create empty report object and load report template:

@code
{
	private StiReport Report;
	private string newValueInput;

 	protected override async Task OnInitializedAsync()
    {
        await base.OnInitializedAsync();

		//Create empty report object
		this.Report = new StiReport();

		//Load report template
		var reportBytes = await Http.GetByteArrayAsync("Reports/ReportWithVariable.mrt");
		this.Report.Load(reportBytes);
	}

...

Then, create method to set variable:

...

	private void SetVariable()
    {
	 	//Get a copy of the report into a new report object
        var report = this.Report.Clone() as StiReport;
        
		//Set new value
        report["MySuperUselessVariable"] = newValueInput;

        //Update view
        report.Render();
		
		//Assign new report to the viewer
		this.Report = report;
    }
}

In the screenshot below you can see the result of the sample code: