function Merge-Templates {
    $Errors = @()
    $MergedConfigurationData = $null
    $MergeFiles = @()
    $AddedDefaultFiles = @{}

    for ($i = 0; $i -lt $selectionList.Items.Count; $i++) {
        $item = $selectionList.Items[$i]
        $file = $item.FullName

        if (-not (Test-Path $file)) {
            $Errors += "Datei nicht gefunden: $file"
            continue
        }

        $directory = Split-Path -Path $file -Parent
        $defaultFiles = @(Get-ChildItem -Path $directory -Filter "*.psd1" -File -ErrorAction SilentlyContinue |
            Where-Object { $_.BaseName -eq "Default" -or $_.BaseName -like "*.Default" } |
            Sort-Object Name)

        foreach($defaultFile in $defaultFiles){
            if(-not $AddedDefaultFiles.ContainsKey($defaultFile.FullName)){
                $MergeFiles += $defaultFile.FullName
                $AddedDefaultFiles[$defaultFile.FullName] = $true
            }
        }

        $MergeFiles += $file
    }

    foreach($file in $MergeFiles){
        try {
            try {
                $TemplateData = Import-PowerShellDataFile -Path $file -ErrorAction Stop
            }
            catch {
                $Errors += "Datei konnte nicht importiert werden: $file"
                continue
            }

            if($null -eq $MergedConfigurationData){
                $MergedConfigurationData = $TemplateData
            }else{
                $MergedConfigurationData = Merge-DSCConfigurationData -Template $MergedConfigurationData -Deployment $TemplateData
            }
        }
        catch {
            $Errors += "Fehler beim Verarbeiten $($file): $($_.Exception.Message)"
        }
    }

    if ($null -ne $MergedConfigurationData) {
        try {
            $script:MergedConfigurationData = $MergedConfigurationData
            $script:ResolvedConfigurationData = Resolve-DSCConfigurationData -ConfigurationData $MergedConfigurationData
        }
        catch {
            $Errors += "Fehler beim Auflösen der ConfigurationData: $($_.Exception.Message)"
            $script:ResolvedConfigurationData = $null
        }

        if($null -ne $script:ResolvedConfigurationData){
            Update-TreeView -ConfigurationData $script:ResolvedConfigurationData
        }else{
            Update-TreeView -ConfigurationData $MergedConfigurationData
        }

        $statusBar.SetText("Status", "Merge erfolgreich: $($selectionList.Items.Count) Queue-Dateien, $($MergeFiles.Count) inklusive Defaults")
    }
    else {
        Update-TreeView -ConfigurationData $MergedConfigurationData
        $statusLabel.Text = "Merge ergab kein Ergebnis"
    }

    if ($Errors.Count -gt 0) {
        [System.Windows.Forms.MessageBox]::Show(($Errors -join "`r`n"), "Merge Warnungen", [System.Windows.Forms.MessageBoxButtons]::OK, [System.Windows.Forms.MessageBoxIcon]::Warning)
        return
    }

    return $script:ResolvedConfigurationData
}